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 mu.scular impressions. 



— 19. Tlie 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; h, the branchial; c, the pallial tentacle; d, the foot; 

 e, the gills; f, the intestine; </, the exterior ligament; h, the border of the mantle. 



Fig. 21 — 4.3. Pecchiola abjssicola. 



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; h, the branchial siphon; d the foot. 



— 32. The anal siphon strongly magnified, seen from the ^ide. 



— 33. Aperture of the same. 



— 34. Some of the superficial conical papilliT 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; f, the thin byssus proceeding 

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



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



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

 both the siphonal apertures. 



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



ture; t, the tentacles; .r, 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; b, the branchial; t. t, the tentacles; x. x, the conical papilla;. 



