xMguitJ ill. j-jiiiiu'jiiia ifiroveisa, lue ;>[jirai, sinisirai wieii. 



22. Cavolina tridentata; an expanded animal with wing-like swimming 

 organs and the projections from the mantle extending out from the side slits of 

 the shell. Fig. 53, the shell. 



24. Creseis conica ; an expanded animal with the tentacles projecting from 

 the wing?. Fig, 25, the slender conical shell. 



26. Flysia catulu-^, the animal with the swimming organs folded over the back. 



27. ^Eolidia pihita; .A, the oral tentacles; B, the dorsal tentacles; G, the 

 external gills in live series. The front angles of the foot can be seen lietween 

 the tentacles. 



25. Doris tuberculata; G, a circle of pinnate, retractile gills. The lamin- 

 ated, dorsal tentacles are also retractile into cavities. 



21). Dendronotus arborescens ; A, antler-like appendages; B, dorsal tentacles ; 

 G, the arborescent gills. 



30. Po'ycera Lessonii ; G, the bipinnate, non-retractile gills forming but a 

 half circle. 



31. Natica dnplicata, the radula or lingual ribbon (also called tongue). All 

 the animals on this plate have some form of radula. 



32. 8ipho Stirapsoni ; a dextral, spira' shell, illustrating various terms used 

 in the descriptions ; A, the anterior end ; 15, the posterior end, the apex of the 

 spire and the nucleus; G, the whores of the spire ; H, the suture ; 1, the body 

 whorl ; E B F, the angle of the spire ; K, the aperture ; J, the inner Jip and 

 the columella; L, an anterior canal ; C, the outer lip ; the distance A K, the 

 length of the sheU ; D C, the diameter or width. The aperture is half the 

 length of the shell; the whorls are eight in number. Fig. 33, the operculum. 



34. Purpura lapillus; the revolving furrows and ridges are very district; 

 the aperture has a notch instead of a canal at the anterior end. 



35. Urosalpinx cinerea ; the rib-like undulations or varices are more distinct 

 than the revolving lines; whorls rounded; suture deep; canal, short. 



3(1 Nas^a irivittata ; the wliorls fattened and shouldered at the suture; sur- 

 face granulated ; the revolving lines and the ribs about equally })roa)inent. 



37. luipleura caudata ; the whorls angulated ; the varices or ribs stout ; the 

 cunal long, straight and narrow. 



35 Natica heros ; a young shell with the three revolving series of blotches ; 

 A, open umbilicus. 



3U. Xatica dnplicata, with the umbilicus nearly covered with a callus at B. 



40. Cre[)idu]a fornicata; side view showing the apex and lines of growth. 



41. The same, under side, with the shelf in the boat-shaped shell. 



42. Acm;ea testudinalis ; side view of the conical shell. Fig. 43, interior view. 



44. < hsetopleura apiculata ; shell composed of eight arched pieces surround- 

 ed by a leather-like material forming a girdle. 



45. Nassa obsoleta ; A, the operculum ; B, the foot ; C, the tentacles with 

 eyes at their outer bases ; D, the siphon. The shell is reticulated. 



46. Melampus lineatus, under side ; the foot with a transverse groove ; the 

 head showing the mouth on the under side. Fig. 47, side view ; the head has 

 one pair of tentacles with eyes at their inner bases. Fig. 48, the shell ; the 

 inner lip with two fold-like teeth. 



49, 50, 51, 52 and 33 show ditierent varieties of opercula. 49 is paucispiral, 

 50 spiral, 51 imbricated Avith a marginal nucleus, 52 concentric, and 33 some- 

 what spiral with an apical nucleus. 



53. llaminea solitaria ; aperture more than half the area of the shell ; a pit 

 in place of spire ; aperture full length of the shell. 



54. Fhiline sinnata ; aperture three-fourths the area; spire rudimentary. 



55. Triforis perversa; a sinistral, turreted shell ; aperture very short. 



56. Spirula Peronii. Fig. 57, the spiral chambered shell with the whorls 

 separated. Fig. 58, Ommatostrephes Bartramii ; 59, the gladius. Fig. 60, Ony- 

 choteiithis Banksli; 61, the gladius. Fig. 62, Loligopsis pavo ; 63, the gladius. 

 Fig. 64, Sepiola atlantica ; 65, the gladius. Fig. 66, Loligo Pealii. 



in Figs. 56-66, there are eight true arm.';, which are sessile, besides which 

 there are two peculiar ones called tentacles. The side projections, usually near 

 the tail, are called tins. 



Figures 24, 25, 30, 32 to 38, 44 to 48 and 55, are about natural size ; 22, 23, 

 28, 29, and 39 to 43, about half size ; 27, one-third size; 26, 31 and 53, are double 

 size ; 21 and 54, are much enlarged (x 5) ; 56 to 66, are much reduced. 



Figures 21 to 30, and 53 to 55, are after figures in Binney Gould's Inv. 

 of Mass. ; 56-66, from Tryon's Am. Marine Conch. The others are original. 



