28 SMITHSONIAN MISCELLANEOUS COLLECTIONS 



Genus LAMBRUS Leach 



33. LAMBRUS RUGOSUS ' Stimpson 



Plate IV, Fig. 3 



Lambrus rugosus Stimpson, Proc. Acad. Nat. Sci. Phila., ix, p. 220 [27], 

 1857. 



Carapax nearly as long as broad, with very irregular and partly 

 tuberculated surface ; front with a deep, smooth, longitudinal con- 

 cavity. An irregularly tuberculated ridge extends on either side 

 obliquely across the branchial region to the posterior of the lateral 

 teeth, enclosing a rather broad and depressed area, in which the 

 granulated cardiac region forms a slight eminence. Beneath the 

 ridge on the branchial region there are three principal tubercles. 

 Lateral margin with about ten teeth, the first at the hepatic edge, 

 rather prominent; the next eight very small, but sharp and deeply 

 cleft, minutely denticulated, and about equal in size ; the posterior 

 tooth elevated and separated from the rest by a short space, large 

 and conical, with a denticle on each side at its base. Posterior mar- 

 gin with four or five very small, distant tubercles only. Rostrum 

 oblique, longer than broad at base, tapering, but with rounded ex- 

 tremity ; a minute marginal tubercle at its base on each side. Chelo- 

 poda of moderate length, rugose, and tuberculated above ; meros 

 with two sharp teeth on the front edge. Hand with the upper sur- 

 face sloping inwards and broadest at the middle, the keels not being 

 parallel ; three large tubercular teeth on outer keel, the third being 

 at the insertion of the dactylus ; six small teeth on inner keel, the 

 middle one sharply prominent, the others less conspicuous. Inferior 

 surface of chelopoda nearly covered with tubercles, which are 

 smooth, rounded, equal, and but little elevated ; of these there are 

 four rows on the infero-exterior surface of the hand. Five or six 

 small teeth on the triangular space at the superior base of the dac- 

 tylus. Ambulatory feet nearly smooth ; a few small spines on the 

 superior edge of the meros. 



In the young female the gastric and branchial regions are more 

 deeply separated ; the rostrum is shorter and blunter and the tuber- 

 cles less numerous on the inferior surface of the chelopoda. 



The dimensions of a male are as follows : Length of carapax, 

 0-34; greatest breadth (at the small ninth or penultimate lateral 

 tooth), 0.35; length of rostrum. 0.07; of chelopod. 0.5 inch. 



"■ ParthcHope ritgosa (Stimpson). 



