MUSEUM OF COMPARATIVE ZOOLOGY. 129 



Of this species there is hut one specimen in the collection, an immature 

 female, the dimensions of which are : Length of carapax, 0.20 ; breadth, 

 0.17 inch. 



It was taken in 15 fathoms, off French Reef, April 3, 1869. 



Family PARTHENOPIDAE. 

 Subfamily PARTHENOPINAE. 



Lambrus crenulatus Sauss. 



Lambrus crenulatus De Saussure, Crust. Nouv. du Mexique et des Antilles, 

 p. 13 ; pi. i, fig. 4. Stimpson, Notes on N. American Crust., p. 73. Des- 

 bonne et Schramm, Crust, de la Guadeloupe, p. 21. 



This species is remarkable for its depressed form and the excavation of 

 the pterygostomian and subhepatic regions, which excavation extends to 

 the infero-exterior margin of the orbit, forming, when- the chelipeds are 

 retracted, covered afferent passages, the external apertures of which are 

 seen between the base of the finger of the cheliped and the margin of the 

 orbit. This arrangement would indicate that the crab habitually conceals 

 itself in the sand, with the rostrum, eyes, and afferent apertures only ex- 

 posed. 



Lambrus laciniatus De Haan exhibits the same features in a less marked 

 degree, and the two species, with three or four similar forms, comprise a 

 group which future studies may prove to be distinct from the triangular 

 Lambri, and for which the name Platylambrus would be appropriate. 



Lambrus crenulatus was taken near the Tortugas in from 5 to 7 fathoms, 

 and off Loggerhead Key in 1 3 fathoms. 



Lambrus Pourtalesii nov. sp. 



Carapax considerably broader than long, with a median row of four 

 spiniform tubercles, of which one is placed upon the gastric and three on 

 the cardiac region. In front of the tubercle on the gastric region there 

 are two much smaller ones in a transverse line. The oblique ridge on the 

 branchial region is armed with three unequal tubercles, and a strong, 

 spiniform, laciniated tooth, with a smaller tooth at its base, at the margin of 

 the carapax. There are a few small, scattering tubercles on the other parts 

 the carapax, particularly in the hollows between the branchial and cardiac 

 regions. The depressions between the branchial, hepatic, and gastric re- 

 gions are moderately deep. The general surface is pitted and granulated, 

 having a carious appearance. There is a small prominent tooth on the 

 hepatic region. Antero-lateral margin, behind the cervical sulcus, with 

 VOL. II. 9 



