77 



Fig. 17. The right valve seen from the outer side. 



18. The same, seen from the inner side, shewing the exterior ligament, the border of 



the hinge, the pallial sinus, and the muscular impressions. 



19. The upper part of the same, more strongly magnified, shewing the cardinal teeth 



and the muscular impressions. 



20. A quite young living specimen with extended foot and siphons, magnified about 8 

 times, a, the anal siphon; b, the branchial; c, the pallial tentacle; d, the foot; 

 e, the gills; /', the intestine; y, the exterior ligament; /i, the border of the mantle. 



Fig. 2143. Pecchiola abyssicola. 



Fig. 21. A perfect shell viewed from the left side, magnified about 5 times. 



22. The same seen from above. 



23. The same seen from behind. 



24. The same; front view. 



25. The right valve seen from the interior side, shewing the pallial line and the mus- 



cular impressions. 



26. The left valve seen from the interior side, a, the small loose ossicle imbedded in 



the ligament. 



27. The upper part of the same, with the umbo, and the ossicle (a). 



28. The border of the hinge seen from below, with the ossicle (a). 



29. A piece of the surface of the shell strongly magnified, shewing the radiating stripes, 

 and the regularly arranged points. 



30. The same in profile, shewing that each of the fine points forms a small conical process. 



31. A living specimen with extended foot and siphons, seen from the left side, a, the 

 anal siphon; 6, the branchial siphon; d the foot. 



32. The anal siphon strongly magnified, seen from the side. 

 33. Aperture of the same. 



34. Some of the superficial conical papillae still more strongly magnified. 



35. A spirit-specimen with the animal and half-open valves seen from below, d, the 



foot half retracted in the oval aperture of the mantle ; t, the thin byssus proceeding 

 from its base; , the tentacles placed around the branchial siphonal aperture. 



36. The same specimen viewed from behind, a, the anal siphonal aperture; &, the 



branchial; t. t, the tentacles^ x. x, the conical tubercles arranged circularly around 

 both the siphonal apertures. 



37. The animal taken out of its shell and seen from above, , the anal siphonal aper- 



ture; t, the tentacles; x, the conical tubercles; o. o, the ovaries. 



38. 4 egg-capsules with eggs enclosed, strongly magnified. 



39. The animal seen from behind, more strongly magnified, a, the anal siphonal aper- 



ture; &, the branchial; t. t, the tentacles; x. x, the conical papillae. 



