PLATE I. 



Fig. I. Operculum Liinacina inflata d'Orb., froni the outside. 



Fig. 2. Stomach Liniacina helicina Phipps, veiitral view. (;, oesophagus; /;, beginning of the intestine; 



c, coecum. 

 Fig. 3. Central nervous system Liinacina lieUcina Phipps, A, ventral view. B, from the left side. C, from 



the right side. 

 p and /', left and right pedal ganglion; v and v , left and right visceral ganglion; c and c', left 



and right cerebral ganglion; i and i', nerves to the fins; 2, left pallial nerve; 3, right pallial 



nerve; 4 and 5, visceral nerves; 6 — 9, nerves to the tentacles and to the lips; 10, cerebral 



commissure; ot and oi , left and right otocyst. 

 Fig. 4. Shell Pcraclis reticulata var. minor. 36 <. 

 Fig. 5. Shell Peraclis rissoides n. sp. 33 ,•'. 

 Fig. 6. Operculum of the same, from the outside. 

 Fig. 7. Shell Pcraclis iiiolucceiisis n. sp. 25 x. 

 Fig. 8. The same, seen from apex. 20 >'. 

 Fig. 9. Fragment of the same, seen from apex. 60 X. 

 Fig. 10. Operculum of the same, seen from the outside. 

 Fig. II. Head Pcraclis rissoides n. sp. Dorsal view. 

 Fig. 12. Jaw Peraclis reticulata var. minor, 2"Q ser. of right jaw. 

 Fig. 13. Pallial gland Pcraclis rissoides n. sp., from the outside. a, "balancer". 

 Fig. 14. Central nervous system Pcraclis rissoides n. sp. A ventral view. B, from the right side. 



Explanation of letters the same as in fig. 3. Besides, /. v., posterior visceral ganglion. 

 Fig. 15. Shell '^ Agadina" n. sp. A, from aperture. B, from umbilicus. 22 - . 

 Fig. 16. Shell (probably abnormal) of Clio (Hyalocylix) striata (Rang). Ventral view. 10 X. 

 Fig. 17. Embryonic shell of Clio (Hyalocylix) striata (Rang). 



Fig. 18. Intestine Clio cuspidata. a, intestine; b, glandular organ, attached to it. 

 Fig. 19. Accessory genital glands Clio (Crescis) acicula (Rang), from the left side. a, efferent duet of the 



gonad; b, accessory genital gland; c, vas deferens (" Vagina" Gegenbaur); cl, receptaculum seminis (?). 

 Fig. 20. Genital organs Clio (Styliola) subuia (Quoy et Gaimard). Dorsal view. 

 Explanation of letters the same as in fig. 19. g, gonad. 



