CilUSTACEA OF ^HE MERaUI ARCHIPELAGO. 13l 



appear in this species quite smooth and ungrooved. On each 

 side of these smooth regions there are therefore three principal 

 grooves nearly parallel to one another and directed obliquely 

 forwards and inwards. The lateral margins are ciliate, present 

 a small emargination immediately behind the external angles of 

 the orbits, and are directed obliquely backwards to the bases of 

 the fourth pair of legs. 



In its general appearance the cephalothorax of D. hrevitarsis 

 resembles that of D. sulcata, but the upper surface is grooved in 

 a different manner. The upper surface is a little broader than 

 long, a little convex longitudinally as well as transversely, and 

 distinctly suleate. The front resembles that of D. sulcata, is 

 strongly deflexed, as in that species, but is less narrowed and 

 more rounded anteriorly. It is broadly grooved, the groove 

 occupying, as in D. sulcata, nearly the whole breadth of the front ; 

 this groove is prolonged backwards, in the middle line of the 

 cephalothorax, to the posterior cardiac region, where it is a little 

 narrowed, and issues into a transverse groove, which runs parallel 

 to the posterior margin of the carapace at a short distance 

 from it. The five-rayed star of grooves, vrhich occurs in D. sul- 

 cata anteriorly, is absent in D. hrevitarsis. The lateral margin 

 is ciliate, and presents a slight emargination immediately bebind 

 the external orbital angle, as in D. sulcata; about its middle, 

 however, the margin is a little curved inward, so that its course 

 is rather sinuous, and it terminates above the base of the 

 last pair of legs. The lateral margiu is bordered, on the upper 

 surface of the carapace, by a groove which corresponds to 

 the groove (a) of D. sulcata, described above ; another groove, 

 proceeding on the epibrauchial region, issues into the lateral 

 groove at about the middle of its length. On each side of 

 the upper surface another transverse groove is found a little 

 behind and parallel to the upper orbital margiu, proceeding 

 from the internal angles of the orbits towards the anterior 

 portion of the lateral margin ; this groove, into which a small 

 and short groove issues about the middle of its posterior mar- 

 gin, is separated from the upper margin of the orbits by an 

 ovoid prominence, furthermore, those portions of the upper 

 surface which lie between the broad median furrow and the 

 grooves («) of the lateral margins are somewhat unequal. The 

 elevated portions of the upper surface, by which the grooves are 



