DIACRIA. 51 



lateral slit emitting the mantle, while in the genera Clio, 

 Balantium, and Styliola the shell is without any lateral 

 fissure ; Vaginella, Theca, and Conularia are fossil genera. 



Genus CAVOLINA, Gioeni. 



Body short, sometimes furnished with lateral appendages. 



Shell globular ; mouth narrower than the internal cavity, 

 with a lateral slit on each side, interrupted in front, 



Spi. Tricla, Betzius. Rheda, Humph. Hyalsea, Lamck. 

 Hyalus, Fror. and Meek. Caulina, Poll. ? Archonta, 

 Montf. ? Glandiolus, Montf. 



Ex. C. tridentata, Forskal^ pi. 6, fig. 1. Shell, C. tri- 

 dentata, fig. 1, a. 



The shells of this genus are globular, with the lateral 

 fissures extending nearly the whole length, and the appen- 

 dices short and directed backwards. The Cavolin(e swim 

 by means of their lateral fins, and when touched retract 

 them and fall to the bottom. 



Species of Cavolina. 



affinis, B'Orh. limbata, UOrh. 



angulata, Eyd. and Soid. longirostris, Lesueur. 



flava, nOrh. pisum, Morch. 



gibbosa, Rang. quadridentata, Lesueur. 



globulosa, Rang. teniobrancbia Peron. 



inflexa, Lesueur. tridentata, Forsk. 



labiata, D'Orb. uncinata, Rang. 



Genus DIACRIA, Gray. 



Body short, sometimes with lateral appendages. 



Shell globular ; mouth narrower than the cavity, with 

 a slit on each side, not interrupted in front ; apex often 

 truncated in the adult. 



