366 LITHOTRYA TRUNCATA. 



Maxilla (PI. X, fig. 12). — These may be described as 

 having their edge formed into three prominences ; or, as 

 having a very wide notch under the two upper great spines, 

 and with the whole inferior part forming two prominences. 

 There are, altogether, about twelve pairs of spines, of 

 which two stand singly on the inferior side of the wide 

 notch under the two upper great spines. The spines on 

 the inferior angle are rather smaller than those above; 

 sides hirsute. 



Outer Maxilla, with the inner margin slightly concave, 

 and sparingly covered with bristles. 



Cirri, imperfectly preserved ; the three posterior pairs 

 have segments of the usual character, bearing five pairs of 

 very long spines, with the usual little intermediate, the 

 minute lateral, and the dorsal spines. First cirrus lost ; 

 second and third with only their few basal segments pre- 

 served, sufficient, however, to show that at least two or 

 three segments, in both the anterior and posterior rami 

 of both cirri, were paved with bristles. 



Pedicels, as in the other species. 



Caudal Appendages, lost. 



This species comes very close, as far as the characters 

 derived from the trophi serve, to the L. truncata, though 

 readily distinguished from that species by the shape of the 

 valves. On the other hand, the capitulum of this species 

 is distinguished with difficulty from that of L. Nicobarica 

 and L. cauta ; no doubt this difficulty is much enhanced 

 by the rostrum and peduncle having been lost. 



5. LlTHOTRYA TRUNCATA. PL IX, fig. 1. 



Anatifa truncata. Quoy et Gaimard. Voyage de l'Astrolabe, 

 PI. xciii, figs. 12 to 15, 1834. 



L. scutis in profundam tergorum plicam insertis : carina 

 crista centrali prominente et rotundatd in parte superiore : 

 rostro et lateribus rudimentalibus, carina latitudinis 

 quindecimam fere partem aquantibus. 



