494 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



but it does not seem desirable to consider such differences, or those in 

 the number of epipods, as of generic vahie. 



Munidopsis crassa, sp. nov. 



This species, which is represented by a single specimen, resembles 

 M. Bairdii in having spine-tipped eye-stalks and the dorsum of the 

 pleou without median teeth or spines, but is at once distinguished from 

 it by the broad and stout non-spined rostrum, the spiny propodi of the 

 ambulatory perseopods, and the very different armament of the carapax. 



Female.-r-ThQ carapax is very broad and the lateral margins nearly 

 parallel. The front is gradually narrowed from between the bases 

 of the peduncles of the antennse into a very broad, stout, triangular, 

 and nearly horizontal rostrum about half as long as the greatest 

 breadth of the carapax, and over the bases of the ocular spines fully 

 half as broad as long. The rostrum is flat or very slightly concave, 

 and nearly smooth beneath, but the dorsal side has a strong median 

 carina and is roughened with small tubercles; the sharp lateral edges 

 are armed with a few minute teeth. There is a prominent acutely 

 triangular spine on the anterior margin over the base of the antenna 

 each side, and outside of this a conical spine directed forward from the 

 angle of the small hepatic region, which really forms the antero lateral 

 angle of the carapax, though the anterior lobe of the branchial region 

 expands laterally much beyond the hepatic region, and is armed at its 

 anterior angle with a great dentiform spine, back of which there are 

 several smaller spines on the lateral margin of this lobe and a single 

 small one at the anterior angle of the posterior branchial lobe. The 

 gastric region is prominent, and armed in front with a pair of sharp 

 conical spines, and back and outside of these with many smaller spines 

 and tubercles, as are also the anterior branchial lobes, and the extreme 

 anterior portions of the branchial and cardiac regions. The cervical 

 suture and the suture between the anterior and posterior lobes of the 

 branchial region are marked by smooth grooves, of which the gastro- 

 cardiac portion of the cervical is the most conspicuous. The whole pos- 

 terior part of the cardiac and branchial regions is armed with sharply 

 crenulated, transverse, and broken rugae with smooth spaces between, 

 and a broader smooth space along the posterior margin, which is armed 

 with a high double crest the edges of which are sharply crenulated. 



The eye-stalks are short, broad, and somewhat cuboidal in form, are 

 capable of very little motion, bear the rather small hemisi)herical white 

 eye partially imbedded at the end, which projects on the dorso mesial 

 side in a slender spine longer than the diameter of the cornea, and are 

 armed with a much smaller spine on the outer edge just back of the eye, 

 and with a very small spine or tubercle similarly situated on the lower 

 mesial angle. 



The stout first segment of the peduncle of the antennula is armed 

 distally with two long spines on the outer side, and beneath with a 



