322 MR. E. J. MIERS'S REVISION OE THE HIPPIDEA. 



The two species known of this remarkable genus are both from 

 the Asiatic Eegion, perhaps the richest in remarkable forms of all 

 the great geographical areas. 



. MASTIGOCHIRrS GRACILIS. PL V. fig. 7. 



Mastigopus gracilis, Stimpson, Proc. Ac. Nat. Sci. Phil. p. 244 (1858). 

 Carapace elongate-ovate, very convex, with short crenulated 

 setose lines. Eront 3-toothed ; the median tooth triangular, the 

 lateral slender, and longer than the median one. Antero-lateral 

 margins 6-toothed, the teeth diminishing in length posteriorly. 

 Eyes slender, and more than half as long as the antennules. 

 Second joint of the maxillipedes oblong, longer than broad. An- 

 terior legs greatly elongated, slender, cylindrical ; the dactylus is 

 longer than the carapace, and consists of 12-14 elongated joints ; 

 terminal joints of the legs of the second and third pairs very 

 slightly falcate. Last segment of the postabdomen elongate, 

 thick, longitudinally sulcate in the middle, and bicarinate near its 

 base. Length about J inch. 



Hub. China Seas {Stimpson, Coll. Brit. Mus.). 

 ' The single example of this species in the national collection 

 w^as presented by the- Smithsonian Institution. 



Mastigochirtjs qtjadrilobatus, sp. n. PI. Y. fig. 8. 



Body elongate-ovate, very convex, marked with short crenulated 

 setose lines, as in the. preceding species. Front 4-lobed, the two 

 median lobes small, rounded, and not nearly as prominent as the 

 spiniform lateral lobes. The striated lateral area is reduced to a 

 narrow line, bordering the whole length of the carapace, which is 

 without lateral marginal teeth. Eyes long, slender, and half as long 

 as the antennules ; second joint of the maxillipedes broad, with the 

 inner margin arcuate. Anterior legs very long, when thrown for- 

 ward longer than the body ; the terminal joint consists of ten or a 

 dozen obscure unequal joints, and is clothed with long fulvous hairs ; 

 the terminal joints of the second and third pairs of legs are long, 

 and very slightly falcate. The outer ramus of the appendages 

 of the penultimate segment is about half as long as the inner. 

 The terminal segment is oblong-lanceolate. Length of carapace 

 5 lines. 



Hah. Philippine Islands, Guimaras {Coll. Brit. Mus.), 

 The form of the front, and the absence of antero-lateral mar- 

 ginal teeth, at once distinguish this species from the foregoing. 



