142 PTEROPODA. 



paulo producto ; apice elongate recto spiniformi. — The dorsal 

 disc (which is not shown) is trilobate and concentrically 

 wrinkled, as partly shown in f. 27. 



17. MDCRONATA, f. 27, Lesueuv. — Quam H. trispinosa 

 brevior et magis expansa ; spinis lateralibus infra medium sub- 

 depressis ; apice breviori.— Shorter and broader than sp. 16, 

 with the lateral appendages placed lower, and the apex 

 shorter. 



Genus CLEODOKA. 



Testa hyalina, trigona, vaginiformis ; apertura trigona vel 

 semiiunari utrinque acute angulata, plerumque in spinam 

 producta ; dorso plerumcjue angulato ; apice acuminato. — 

 The lower lateral appendages of Hyalsea are wanting in this 

 genus, but in most cases the angles of the mouth are pro- 

 duced into spines. 



18. CUSPIDATA, f. 30. — Vagina trigona, disco ventrali ro- 

 tunde tumido, dorso angulato carinato, concentrice rugato ; 

 apertura subtrigona, labro in spinam elongatam acurainatim 

 producto, angulis lateralibus utrinque longispinosis, apice 

 producto. — The side angles of the aperture are low down in 

 the shell, and then produced into two long upturned spines. 

 The labrum is trigonal, and elongated into another spine, the 

 apex being also produced and sharp. The back disc is 

 beautifully wrinkled on each side of the angle. 



19. PYiiAMiDATA, f. 32, Quoy. — Vagina trigona loevi ; 

 disco ventrali subangulatim tumida ; disco dorsali medio 

 angulato, carinato ; apertura trigona, acute producta, ad 

 latera utrinque subspinosa ; apice acuminato. — Resembling 

 sp. 18, but the lateral incisions of tlie aperture are not pro- 

 longed, and the angles are not developed into spines, although 

 very acute. 



