100 



NILS HJ. ODHNER, STUDIES ON RECENT CHAMIDAE. 



Fig. 27. Pseudochama pusilla n. sp. Nervous system. 



Fig. 28. Echinochama arcinella Linné. General habitus of the animal. X 3. 



Fig. 29. Echinochama arcinella Linné. Anatomy of the visceral liump. 



Fig. 30. Echinochama arcinella Linné. Nervous system and surrounding parts of the body. 



Fig. 31. 



Fig. 32. 



Fig. 33. 



Fig. 34. 



Fig. 35. 



Fig. 36. 



Fig. 37. 



Fig. 38. 



Fig. 39. 



Echinochama 



system. 



Echinochama 



septa. 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Plate 4. 



arcinella Linné. Schematical view of the structure of gills and intrabranchial blood 

 arcinella Linné. Schematical view of the alternation and vascularisation of the branchial 



exogyra Conrad. 

 exogyra Conrad. 

 exogyra Conrad. 

 exogyra Conrad. 

 exogyra Conrad. 

 ferruginea, Reeve. 



Morphology of the animal. X 2,5. 

 Intestinal and circulatory systems. 



General habitus of the right nephridium; the pericardial tube cut open. 

 Horizontal section through the nephridia at the place of communication. 

 Schematical view of the nephridia from above. 

 General habitus of the adult animal. X 2. 



ferruginea Reeve. General habitus of a young specimen from Barthelemy. X 1 5. 



Fig. 40. 



Fig. 41. 



Fig. 42. 



Fig. 43. 



Fig. 44. 



Fig. 45. 



Fig. 46. 



Fig. 47. 



Fig. 48. 



Fig. 49. 



Fig. 50. 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



open. 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



Pseudochama 



ferruginea 

 ferruginea 

 ferruginea 

 ferruginea 

 ferruginea 

 ferruginea 



Reeve. 

 Reeve. 

 Reeve. 

 Reeve. 

 Reeve. 

 Reeve. 



retroversa Lischke. 

 retroversa Lischke. 

 retroversa Lischke. 

 retroversa Lischke. 

 cristella Lamarck. 



Plate 5. 



Alimentary and circulatory systems. 



Nervous system. 



Schematical view of the nephridia of the young specimen. 



Right nephridium of the young specimen. 



Schematical view of the nephridia of the adult stage. 



Right nephridium of the adult specimen; the pericardial tube cut 



General habitus of the animal. X 2. 

 Alimentary and circulatory systems. 

 Right nephridium ; pericardial tube cut open. 

 Nephridia seen from above. 

 General habitus of the animal. X 2,5. 



Fig. 



51 



Fig. 



52 



Fig. 



53 



Fig. 



54 



Fig. 



55 



Fig. 



56 



Fig. 



57 



Fig. 



58 



Fig. 



59 



Plate 6. 



Pseudochama cristella Lamarck. Alimentary and circulatory systems. 



Pseudochama cristella Lamarck. Right nephridium; the pericardial tube cut open. 



Pseudochama cristella Lamarck. Nephridia seen from above. 



Chama reflexa Reeve. General habitus of the animal. X 2. 



Chama reflexa Reeve. Alimentary canal and arteriae. 



Chama reflexa forma jukesi Reeve. General habitus of a full-grown specimen. X 2,5. 



Chama reflexa forma jukesi Reeve. Alimentary canal and arteriae of the adult stage. 



Chama reflexa forma jukesi Reeve. Nervous system. 



Chama reflexa forma jukesi Reeve. Young specimen with the posterior demi-branch still only indi- 



cated by a series of simple filaments. X 20. 



Plate 7. 



Fig. 60. Chama reflexa forma jukesi Reeve. Schematical view of the structure and the blood vessels of the 



gill. 

 Fig. 61. Chama reflexa forma jukesi Reeve. Right nephridium of the adult stage. 



