38 CH-KTOPLEURA. 



t. 19, f. 116 (not t. 15, f. 81). SOWB. Conch. Illustr. f. 56. Chcs- 

 toplt irensis CrR. MS. ; C. apparata and Callistochiton rufi- 



costaim CPR., olim. Cluetopleura janeirensis DALL, Bull. 37, U. S. 

 Nat. MH-. ]>. M'1i'hitnn segmentatus REEVE, Conch. Icon. t. 23, 

 .. / 'It if on (Chcelopleura) asper SHUTTLW., Jour, de Conchyl. 

 1856, p. 169. 



Tli is species is much elongated, about twice as long as broad- 

 The sculpture of the end valves and lateral areas consists of coaix -. 

 nodulous ribs, which are quite unlike the clear-cut pustules of C. 

 meet, etc. 



Young specimens have only two or three nodulous ribs on the 

 lateral areas. 



The C. segmentatus of Reeve (pi. 13, figs. 61, 62) differs in no 

 way from the type. 



C. SPINULOSA Gray. PL 13, figs. 63, 64. 



Shell ashen, partially tessellated with dark and light at the 

 sutures, and stained with brown on some of the jugular areas. 

 Jugum very acute, elevated. Mucro median, not much raised, the 

 posterior slope very concave. Jugal area not distinct; central 

 areas having about 22 rows of very fine granules on each side of 

 the otherwise smooth areas ; lateral areas much raised, having 

 about 10 rows of radiating grains, separate, sparse; grains very 

 irregular and sparse on terminal valves. 



Interior: Anterior valve with 10, central valves 1, posterior 

 valve 9 slits. Teeth not very sharp but Ischnoid, the posterior 

 slightly niLrulose. Sinus smooth, channelled, broad, deep, the 

 cting jugular sculpture of the outside giving a faint appear- 

 ance of denticulation. Eaves moderate, not spongy. Interior 

 whitish, with two rays of chestnut. 



Length 31, breadth 15* mill. 



Rio Janeiro. 



Ch'r nlosus GRAY, Spicil. Zool. p. 6, t. 6, f. 7, 7a. Sowb., 



Conch. 111. f. 84, 84a. REEVE, Conch. Icon. t. 27, f. 90. Chceto- 

 a CI-R., MS. 



It is doubtful whether the C. spinulom of Sowerby, Reeve and 

 Carpenter is the same as the form originally so named by Gray. 

 Carpenter's description, given above, is drawn from a single speci- 

 men, which apparently served Reeve for his illustration. This 

 specimen i- much injured, having lost its girdle, and some of the 



