MK. E. J. MIEES'S EEYISION OF THE HIPPIDEA. 321 



ramus of the appendages of the penultimate segment but little 

 longer than the outer. Last segment oblong-lanceolate. 



Hob. Cape St. Lucas (Stimpson, Coll. Brit. Mus.). 



The broad striated area on tTie sides of the carapace at once 

 serves to distinguish this species. The three specimens of this 

 species in the British-Museum collection from the Smithsonian 

 lustitution are of small size, length of the carapace of the largest 

 not exceeding ^^ inch (Stimpson gives 1 inch as the length of the 

 carapace). The median frontal projection is very obscure ; and in 

 one specimen the anterior margin appears nearly straight. 



Eemipbs teuncatifeofs, sp. n. PL Y. figs. 5, 6. 



Body depressed ; frontal margin straight, entire, smooth, with 

 scarcely any trace of a median frontal lobe. Sides of the carapace 

 without any trace of the defined striated marginal area existing 

 in other species of the genus. Eye-peduncles very slender, pro- 

 jecting but little beyond the rather prominent penultimate joint 

 of the antennules ; cornea small, subterminal. Anterior legs small 

 and slender; terminal joint of the second and third pairs of legs 

 short, broad at base, distinctly falcate, with the distal portion 

 much slenderer than the proximal. Outer ramus of the append- 

 ages of the penultimate segment of the postabdomen much 

 shorter than the inner. Terminal segment oblong-lanceolate. 



Hab. China {J. R. Beeves, Usq., Coll. Brit. Mus.). 



The obsolescence of the median frontal lobe, and the absence of a 

 lateral marginal striated area, serves to characterize this species. 

 The eye-specks, viewed from above, are placed at a little distance 

 from the distal extremity of the peduncle. The single specimen 

 in the British-Museum collection is a female. Length of cara- 

 pace -^^ inch. 



Mastigochietjs. 



Mastigopus*, Stimpson, Proc. Ac. Nat. Sci. Phil. p. 230 (1858) (nom. 

 prseoc). 



Antennules and antennae short. Third maxillipedes rather 

 slender. First legs very long and very slender, with the last 

 joint especially greatly elongated and multiarticulate. 



* This name was adopted in 1853 by Leuckart (Wiegm. Archiv f. Naturg. 

 xix. p. 258) for a curious Macrurous Crustacean. I have, therefore, altered the 

 termination, whilst retaining the allusion to the whip -like character of the 

 anterior legs. 



