332 GENUS LITHOTRYA. 



Genus — Lithotrya. PL VIII, IX. 



Lithotrya. G. B. Sowerby. Genera of Shells, April 1822. 

 Litholepas. Be Blainville. Diet, des Scienc. Nat., 1824. 

 Absia.* Leach. Zoological Journal, vol. ii, July 1825. 

 BmsNiEUS et conchotrya. /. E. Gray. Annals of Philosophy, 



vol. x, (new series,) August 1825. 

 Lepas. Gmelin. Systema Naturae, 1789. 

 Anatifa. Qaoy et Gaimard. Voyage de 1' Astrolabe, 1832, 



Valvce 8, si inter eas parvum (satpe rudimentale) rostrum 

 et duo par v a later a numerentur ; incrementi lineis concinne 

 crenatis : pedunculus squamis calcareis parvis vestitus, in 

 verticillis superioribus crenatis ; aut calyci basali calcareo 

 aut discorum ordini affixus. 



Valves 8, including a small, often rudimentary rostrum 

 and a pair of small latera : lines of growth finely crenated. 

 Peduncle covered with small calcareous scales, those of 

 the upper whorls crenated; attached either to a basal 

 calcareous cup, or to a row of discs. 



Body lodged within the peduncle : mandibles with 

 three teeth, the interspaces being pectinated; maxillae 

 various : olfactory orifices slightly prominent : caudal 

 appendages multiarticulate. 



Lodged in cavities, bored in calcareous rocks, or shells, or corals ; generally 

 within the Tropics. 



Description. — The capitulum is not much compressed, 

 a horizontal section giving an oval figure ; it is placed 

 obliquely on the peduncle, the scuta descending lower 

 than the terga and carina. There are eight valves, of 

 which the scuta, terga, and carina are large ; the rostrum 

 and a pair of latera are very small and often rudimentary. 

 These three latter valves are essentially distinguished from 

 the scales of the peduncle, the upper ones of which they 



* The description of Absia is so inaccurate, that I should not have recog- 

 nised it, had not the Lithotrya Nicobarica, in a bottle in the British Museum, 

 borne this name. 



