46 CALIFORNIA ACADEMY OF SCIENCES. 



angle of the merus rounded. A ridge on the pterygostomian regions. 

 Chelipeds trigonal, the angles dentate. Ambulatory legs slender, com- 

 pressed; dactyls slender, depressed. 



Type. — L. punctatissimus (Owen). 



Leiolambrus punctatissimus (Oiven), 



Parthenope punctatissima Owek, Zool. Beechy's Voyage, Crust., 1839, p. 

 81, PI. XXIV, fig. 4. Stimpson, Journ. Bost. Soc. Nat. Hist., Vol. VI, 

 1857, p. 458. LocKTNGTON, Proc. Cal. Acad. Sci., Vol. VII, 1877, p. 78. 



Leiolambrus punctatissimus A. Milne-Edwards, Miss. Sci. au Mex., Vol. 

 I, Pt. V, pp. 148 and 159. 



Carapace smooth, convex, minutely punctate; the median and cardiac 

 regions forming a nearly continuous loagitudinal elevation, bounded on 

 either side by a conspicuous, longitudinal depression. Front truncated, 

 having a small, median tooth, behind which the upper surface is marked 

 with a short, longitudinal groove. Postorbital angle acute. Antero-lateral 

 margins long, slightly arcuated, and furnished with teeth which become 

 very small toward the anterior end. The sides of the carapace are pro- 

 duced into a prominent, triangular tooth. Two teeth on the posterior mar- 

 gin near the middle line; external to these a pair of larger marginal teeth; 

 the margins between the external pair and the lateral angles of the carapace 

 are concave. The whole posterior margin of the carapace is marked with 

 a delicate, raised, jagged line; another fine raised line running upon the 

 branchial regions from the external tooth of the posterior margin. Max- 

 illipeds smooth, the ischium slightly narrowed distally, the antero -internal 

 angle produced forward into a rounded lobe; merus broadly rounded at the 

 antero-external angle and produced below the articulation of the palp. 

 Chelipeds large; merus with the angles denticulated, the anterior edge 

 bearing several rough teeth; carpus with the angles denticulated, the 

 outer margin acute and dentate; hand longer than the merus, the margins 

 denticulated, the upper margin upturned near the end; pollex nearly 

 longitudinal and almost straight, the inner margin dentate; dactyl curved 

 and provided on the external portion of the base with two converging, 

 denticulated ridges which meet and form a crest on the distal portion. 

 Ambulatory legs smooth, compressed, and subequal in length; dactyls 

 slender, lanceolate, longer than the propodi, and flattened in a plane at 

 right angles to that of the preceding joints. 



Locality of specimen described, lat. 27° 45' N., Ion. 110° 45' W.; 

 20 fathoms. 



Length of carapace 7.25 mm. 



Width of carapace 9.5 mm. 



Length of hand 7 mm. 



