SCLEROCEANGON PROCAX. 135 



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

 above described. 



Sclerocrangon procax Fax. 

 Plate XXXVI. 



Bull. Mus. Couip. Zuol., XXIV. 199, 1S93. 



Rostrum small, simple, acute, inclined npward 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 the 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 ont into long, acute spines that 

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

 on each side of the carapace, and meets a similar ridge running fiom 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 carinre. From the 

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

 the branchial regions, meeting an interrupted ridge which extends from 

 the antero-lateral 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 supjolanted 

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

 of the abdomen on each side, at the npper boundary of the pleurae. 

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

 as one passes backward nntil 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 flanked 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'. agassizii Smith, with the following exceptions : the two 

 flagella of the first pair of antennae in the male are subeqtual in length, while 

 in the male of S. agamzii the outer flagellum is much longer than the inner ; 

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



