Mr. A. Adams on Cavolina^ JDiacria, and Pleuropus. 45 



6. C. longirostris, Lesueur. 

 Hyalsea limbata, B'' Orb. 

 ecaudata, Lesueur. 



Hob. Atlantic and Indian Oceans ; China Sea. The H. ecau- 

 data of Lesueur is only a short-beaked variety, and D'Orbigny's 

 H. limbata is merely a large variety. 



7. C. angulata, Souleyet. 

 Hah. Indian Ocean. Common. This offers some peculiari- 

 ties, but seems merely to be a small variety of C. longirostris. 



8. C. Orbigniji, Rang (fossil). 

 Hyalsea aquensis, Gratel. 



Subgen. Orbignyia, A. Ad. 



9. C. inflexa, Lesueur. 

 Hyalaea elongata, Lesueur. 



1 depressa, D'Orb. 



uncinata, Honingh. 



vaginella, Cantr. 



Hob. Atlantic and Indian Oceans. Rather abundant. 



10. C. labiata, D'Orb. 



Hab. Atlantic and Indian Oceans and China Sea. Less 

 common than the former. 



These two species are Cavolince much elongated, and present 

 a peculiar appeai'ance compared with the typical forms. 



Gen. DiACRiA, Gray. 

 1. D. trispinosa, Lesueur. 

 Hyalsea mucronata, Quag & Gaim. 



triacantha, Guidotti. 



depressa, Bivona. 



Hab. Common in the Atlantic and Indian Oceans. 



Gen. Pleuropus, Eschsch. 



1. P. pellucidus, Eschsch. 

 Cleodora pleuropus, Rang. 

 Hab. ? Mediterranean. 



2. P. longifilis, Trosch. 

 Hab. Mediterranean. 



