SCLEROCKANGON PKOCAX. 



135 



narrower and less convex along its internal margin than it is in the species 

 above described. 



Sclerocrangon procax Fax. 



. Plate XXX VI. 



Bull. Mus. Comp. ZooL, XXIV. 199, 1893. 



Rostrum small, simple, acute, inclined upward at an angle of 45% not 

 longer than the spines at the external orbital angle, overshadowed by the 

 great anterior spine of the dorsal carina of the carapace. This carina is 

 armed with two spines ; the anterior of these is very long, nearly erect, and 

 arises from a point just back of the rostrum; the posterior is shorter and 

 curved forward; between these two spines is the rudiment of a third, 

 anterior to the middle of tlie carina. The external orbital spines, as 

 before said, reach as far forward as the tip of the rostrum. The antero- 

 external angles of the carapace are drawn out into long, acute spines that 

 trend upward and outward. From the orbital spine a ridge riuis backward 

 on eacli side of the carapace, and meets a similar ridge running from the 

 posterior margin of the carapace forward to a lateral spine on the front 

 part of the branchial region. There is another small spine on each side 

 of the gastric region between the median and lateral carinae. From the 

 lower side of the lateral spine a ridge runs downward and backward 6n 

 the branchial regions, meeting an interrupted ridge which extends from 

 the antero-latei^al spines nearly to the posterior margin of the carapace. 

 A flat-topped median dorsal ridge extends along the abdomen from the 

 first to the fifth somites; on the sixth somite this ridge is supplanted 

 by a pair of carina?. An indistinct and interrupted ridge runs the length 



of the abdomen on each side, at the 



r boundary of the pleura9. 



The first pleura ends below in a sharp tooth; this tooth becomes smaller 

 as one passes backward until it disappears in the pleura of the fourth 

 somite. The telson is long, quadrangular in cross-section, grooved above, 

 acute at posterior end ; its base is fianked by a pair of spines arising from 

 the hind end of the sixth abdominal somite. The eyes are small ; a small 

 tubercle arises from the superior margin of the cornea. The appendages 

 are like those of S. agassidl Smith, wath the following exceptions : the two 

 flagella of the first pair of antennce in the male are subequal in length, while 

 in the male of 8, agassizii the outer flagellum is much longer than the inner; 

 the scale of the second antenna is narrower; tlie terminal segment of the inner 



