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appears a little longer, sometimes shorter than its distance from the extremity of the rostrum. 

 Whereas the upper margin is more or less strongly curved, the lower is more or less distinctly 

 concave; it is usually armed ncar the tip with one tooth, often smaller than those of the upper 

 border, more rarely with two teeth, that are situated near one another. 

 The toothing-formulae of 42 specimens are the following: 



5-±-i in 1 2 males and o females. 



^-i^ in X males and 2 females. 



^-iJ in 4 males and 6 females. 



^-^ in 1 male and 3 females. 



?-±^ in I female. 



I 



i±^ in I female. 



2 



The rostrum that measures a little more than one-third the rest of the carapace, gradually 

 narrows distally, its height at the base being one-fourth its length. The sides of the rostrum 

 are o-rooved from the tip to the base; this groove, that gradually widens backward, is defined 

 by two ridges, of which the upper is rounded and broader than the lower, that is situated much 

 nearer to the lower than to the upper margin of the rostrum. The rostral carina does not 

 extend backward beyond the epigastric tooth, it disappears even before reaching the level of 

 the cervical groove; behind the latter the carapace is rounded, as in Halip. niodestiis [S. I. Smith) 

 and it appears here also slightly convex longitudinally. 



Outer orbital angle rounded, little prominent. The spiny armature of the carapace, 

 agreeing with that of Halip. diomedeae Faxon (in: Memoirs Museum Comp. Zool. at Harvard 

 Coll. Vol. XVIII, 1895, p. 186, PI. G), consists of a tolerably strong and well buttressed, 

 post-antennular (antennal) spine, a much smaller branchiostegal spine on the antero-inferior 

 angle of the carapace at the anterior end of the subhepatic groove, a hepatic spine as small 

 as the branchiostegal, a fourth, a little larger, situated behind the antennal spine, nearly in 

 the same horizontal line, though a little below it and one and a half as far distant from it 

 as from the cervical groove, finally a fifth spine, the smallest of all, in the same horizontal 

 line as the antennal spine, immediately behind the cervical groove. Cervical groove well cut, 

 extending up to near but not across the dorsal median line of the carapace, which it therefore 

 does not indent; its antero-inferior portion (or subhepatic groove) is also well developed and 

 terminates immediately behind the branchiostegal spine. The transverse branchiostegal groove, 

 that runs just below the hepatic spine and anteriorly unites with the cervical groove, is as much 

 developed as the subhepatic and ends just behind the level of the 5"^ spine described above; 

 a little farther backward this furrow reappears as the branchio-cardiac groove, which in a sinuous 

 course runs obliquely upward and backward to near the posterior margin of the carapace. 

 This groove, less deep than the cervical furrow, in some specimens ends abruptly not far from 

 the posterior margin of the carapace, while in other ones it gradually widens backward and 

 gradually fades away. In the very young specimen from Stat. 212 the branchiostegal and the 

 branchio-cardiac groove are continuous, not separated from one another. The arcuate, antennal 



39 



