SCLEROCRANGON PROCAX. 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 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 out 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 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 carine. 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 supplanted 
by a pair of carine. An indistinct and interrupted ridge runs the length 
of the abdomen on each side, at the upper boundary of the pleure. 
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 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 antennz in the male are subequal in length, while 
in the male of S. agassizii the outer flagellum is much longer than the inner ; 
the scale of the second antenna is narrower; the terminal segment of the inner 
