Description: English: The shell of Janthina exigua Lamarck, 1816[1] in sand; from New Plymouth, North Island of New Zealand. Part of the photo was removed to highlight the shell. Date: 12 November 2020. Source: Original image filed on iNaturalist.org. Author: Naturewatchwidow.
Description: English: Plate 85. Ianthina fragilis. Common Oceanic Snail—upper and lower figures. Modern accepted name (2012) is Janthina janthina[1]. Ianthina globosa. Globular Oceanic Snail—middle figures. Modern orthography is Janthina globosa[2]. Date: February 1821. Source: Zoological Illustrations, Volume II. Author: William Swainson, F.R.S., F.L.S.
Description: Janthina globosa Swainson, 1823 - purple sea snail shell from Aruba (apical view; modern, latest Holocene; 2.3 cm across at its widest). The Janthina purple sea snail is a remarkable organism. The snail makes a thin calcareous shell that is dark purple-colored in the lower parts and pale to light purplish-colored in the upper parts. This is a good example of reverse countershading. Ordinary countershading involves organisms, such as halibut fish, having dark-colored uppersides and light-colored lowersides. This makes it difficult for predators to see them from above or from below. Janthina is reverse countershaded. One would surmise that the purple sea snail's body is therefore upside-down while it is the water. This is exactly the situation. Janthina makes a bubble raft and the shell is oriented spire-downward (or close to it). The result is an organism that is dark on top and light on bottom. Janthina is a part of the macrozooplankton in the world's oceans. It's bubble raft keeps it from sinking in the water column. It preys on jellyfish-like medusiform organisms such as Physalia, Velella, and Porpita (Phylum Cnidaria, Class Hydrozoa). In ancient times, one source of purple dye for clothing was Janthina purple sea snails. Classification: Animalia, Mollusca, Gastropoda, Janthinidae Locality: Bare Ass Beach, northeastern shore of Aruba, southwestern-most Lesser Antilles, southern Caribbean Sea The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores. Date: 13 November 2014, 17:32. Source: Janthina globosa (purple sea snail) 2. Author: James St. John.
Description: Janthina globosa Swainson, 1823 - purple sea snail shell from Aruba (umbilical view; modern, latest Holocene; 2.3 cm across at its widest). The Janthina purple sea snail is a remarkable organism. The snail makes a thin calcareous shell that is dark purple-colored in the lower parts and pale to light purplish-colored in the upper parts. This is a good example of reverse countershading. Ordinary countershading involves organisms, such as halibut fish, having dark-colored uppersides and light-colored lowersides. This makes it difficult for predators to see them from above or from below. Janthina is reverse countershaded. One would surmise that the purple sea snail's body is therefore upside-down while it is the water. This is exactly the situation. Janthina makes a bubble raft and the shell is oriented spire-downward (or close to it). The result is an organism that is dark on top and light on bottom. Janthina is a part of the macrozooplankton in the world's oceans. It's bubble raft keeps it from sinking in the water column. It preys on jellyfish-like medusiform organisms such as Physalia, Velella, and Porpita (Phylum Cnidaria, Class Hydrozoa). In ancient times, one source of purple dye for clothing was Janthina purple sea snails. Classification: Animalia, Mollusca, Gastropoda, Janthinidae Locality: Bare Ass Beach, northeastern shore of Aruba, southwestern-most Lesser Antilles, southern Caribbean Sea The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores. Date: 13 November 2014, 17:33. Source: Janthina globosa (purple sea snail) 3. Author: James St. John.
Description: Janthina globosa Swainson, 1823 - purple sea snail shell from Aruba (lateral view; modern, latest Holocene; 2.3 cm across at its widest). The Janthina purple sea snail is a remarkable organism. The snail makes a thin calcareous shell that is dark purple-colored in the lower parts and pale to light purplish-colored in the upper parts. This is a good example of reverse countershading. Ordinary countershading involves organisms, such as halibut fish, having dark-colored uppersides and light-colored lowersides. This makes it difficult for predators to see them from above or from below. Janthina is reverse countershaded. One would surmise that the purple sea snail's body is therefore upside-down while it is the water. This is exactly the situation. Janthina makes a bubble raft and the shell is oriented spire-downward (or close to it). The result is an organism that is dark on top and light on bottom. Janthina is a part of the macrozooplankton in the world's oceans. It's bubble raft keeps it from sinking in the water column. It preys on jellyfish-like medusiform organisms such as Physalia, Velella, and Porpita (Phylum Cnidaria, Class Hydrozoa). In ancient times, one source of purple dye for clothing was Janthina purple sea snails. Classification: Animalia, Mollusca, Gastropoda, Janthinidae Locality: Bare Ass Beach, northeastern shore of Aruba, southwestern-most Lesser Antilles, southern Caribbean Sea The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores. Date: 13 November 2014, 17:33. Source: Janthina globosa (purple sea snail) 1. Author: James St. John.
Description: English: Illustration of Janthina janthina (Linnaeus, 1758)[1] seashell; taken from Fibuier, Louis (1868) Ocean World: Being a Descriptive History of the Sea and its Living Inhabitants. New York: D. Appleton & Co. Date: 8 November 2020. Source: Original filed on Wikimedia Commons. Author: Fibuier, Louis.
Description: English: Two shells of Janthina janthina (Linnaeus, 1758)[1] with their air floats with hardened mucus; from Manukau Harbour, Kaitarakihi Bay (eastern end of beach), North Island of New Zealand. Date: 8 November 2020. Source: Original image filed on iNaturalist.org. Author: Lange, Peter de.
Description: Janthina janthina Linnaeus, 1758 - purple sea snail shell from Texas, USA (lateral view; modern, latest Holocene; ~2.35 cm across at its widest). The purple sea snail is a remarkable organism. There are several valid, named species, but the most common and widespread form is this - Janthina janthina. The snail makes a thin calcareous shell that is dark purple-colored in the lower parts and whitish to pale purplish-colored in the upper parts. This is a good example of reverse countershading. Ordinary countershading involves organisms, such as halibut fish, having dark-colored uppersides and light-colored lowersides. This makes it difficult for predators to see them from above or from below. Janthina is reverse countershaded. One would surmise that the purple sea snail's body is therefore upside-down while it is the water. This is exactly the situation. Janthina makes a bubble raft and the shell is oriented spire-downward (or close to it). The result is an organism that is dark on top and light on bottom. Janthina is a part of the macrozooplankton in the world's oceans. It's bubble raft keeps it from sinking in the water column. It preys on jellyfish-like medusiform organisms such as Physalia, Velella, and Porpita (Phylum Cnidaria, Class Hydrozoa). In ancient times, one source of purple dye for clothing was Janthina purple sea snails. Classification: Animalia, Mollusca, Gastropoda, Janthinidae Locality: unrecorded post-storm Gulf of Mexico beach, coastal Texas, USA The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores. Date: 13 November 2014, 16:26. Source: Janthina janthina (purple sea snail) 1. Author: James St. John.
Description: Janthina janthina Linnaeus, 1758 - purple sea snail shell from Texas, USA (apical view; modern, latest Holocene; ~2.35 cm across at its widest). The purple sea snail is a remarkable organism. There are several valid, named species, but the most common and widespread form is this - Janthina janthina. The snail makes a thin calcareous shell that is dark purple-colored in the lower parts and whitish to pale purplish-colored in the upper parts. This is a good example of reverse countershading. Ordinary countershading involves organisms, such as halibut fish, having dark-colored uppersides and light-colored lowersides. This makes it difficult for predators to see them from above or from below. Janthina is reverse countershaded. One would surmise that the purple sea snail's body is therefore upside-down while it is the water. This is exactly the situation. Janthina makes a bubble raft and the shell is oriented spire-downward (or close to it). The result is an organism that is dark on top and light on bottom. Janthina is a part of the macrozooplankton in the world's oceans. It's bubble raft keeps it from sinking in the water column. It preys on jellyfish-like medusiform organisms such as Physalia, Velella, and Porpita (Phylum Cnidaria, Class Hydrozoa). In ancient times, one source of purple dye for clothing was Janthina purple sea snails. Classification: Animalia, Mollusca, Gastropoda, Janthinidae Locality: unrecorded post-storm Gulf of Mexico beach, coastal Texas, USA The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores. Date: 13 November 2014, 16:17. Source: Janthina janthina (purple sea snail) 2. Author: James St. John.
Description: English: Illustration of Janthina janthina (Linnaeus, 1758) alive with the animal ("FL": float; "O" : eggs; "Pr": proboscis; "Br": branchiae; "F": foot); taken from Cooke, A. H.; Shipley, A. E.; Reed, F. R. C. (1895) Molluscs, Cambridge Natural History, v.3, London: Macmillan and Co. Date: 9 November 2020. Source: Original filed on Wikimedia Commons. Author: Cooke, A. H. Shipley, A. E. Reed, F. R. C.
Description: English: A seashell of the Epitoniidae Janthina janthina (Linnaeus, 1758)[1]; from Ripiro Beach, south of Omamari Stream, Northland, North Island of New Zealand. Edited photo with darker colors. Date: 8 November 2020. Source: Original image filed on iNaturalist.org. Author: Lange, Peter de.
Description: Janthina janthina Linnaeus, 1758 - purple sea snail shell from Texas, USA (umbilical view; modern, latest Holocene; ~2.35 cm across at its widest). The purple sea snail is a remarkable organism. There are several valid, named species, but the most common and widespread form is this - Janthina janthina. The snail makes a thin calcareous shell that is dark purple-colored in the lower parts and whitish to pale purplish-colored in the upper parts. This is a good example of reverse countershading. Ordinary countershading involves organisms, such as halibut fish, having dark-colored uppersides and light-colored lowersides. This makes it difficult for predators to see them from above or from below. Janthina is reverse countershaded. One would surmise that the purple sea snail's body is therefore upside-down while it is the water. This is exactly the situation. Janthina makes a bubble raft and the shell is oriented spire-downward (or close to it). The result is an organism that is dark on top and light on bottom. Janthina is a part of the macrozooplankton in the world's oceans. It's bubble raft keeps it from sinking in the water column. It preys on jellyfish-like medusiform organisms such as Physalia, Velella, and Porpita (Phylum Cnidaria, Class Hydrozoa). In ancient times, one source of purple dye for clothing was Janthina purple sea snails. Classification: Animalia, Mollusca, Gastropoda, Janthinidae Locality: unrecorded post-storm Gulf of Mexico beach, coastal Texas, USA The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores. Date: 13 November 2014, 16:16. Source: Janthina janthina (purple sea snail) 3. Author: James St. John.