NO. 3 GARTH : SOME NEW SPECIES OF BRACHYURAN CRABS 63 



Genus MITHRAX Latreille 



Subgenus Mithrax 



Mithrax (Mithrax) clarlonensis, new species 

 Plate 15, Figs. 1-3 



Type: Female, holotype. Cat. No. 78777, U.S. National Museum, 

 from Sulphur Bay, Clarion Island, Mexico, 57 fathoms; January 5, 

 1934; collected at Velero Station 137-34. Female, paratype, Cat. No. 

 341, Allan Hancock Foundation, The University of Southern Cali- 

 fornia, from the same locality, 15 fathoms; June 11, 1934; collected 

 at Velero Station 305-34 by the Allan Hancock Expedition of summer 

 1934. Five males and five females (three ovigerous), paratypes, same 

 locality, 28-43 fathoms; March 16, 1939; collected by Allan Hancock 

 Expedition of 1939 at Velero Station 917-39. 



Measurements: Female holotype: length 12.9 mm., width between 

 fourth lateral spines 12.5 mm., greatest width 12.9 mm., length of 

 cheliped 17.0 mm., of chela 8.0 mm. Largest male paratype: length 10.4 

 mm., width 10.2 mm. 



Diagnosis: Width and length of carapace equal. Three spines on 

 basal antennal article, middle spine curving inward. Three denticles on 

 supraorbital margin between pre- and postorbital teeth. Areoles of cara- 

 pace finely tuberculate. Anterolateral prominences sharply compound 

 tuberculate. Base of hand paved with rounded granules. 



Description: Carapace ovoid, relatively broad, width as great as 

 length, areolate, the areoles abundantly studded with small, sharp 

 tubercles and finer granules; furrows separating gastric and cardiac 

 from branchial regions smooth and deep. Frontal lobes short, quadri- 

 denticulate, and separated by a U-shaped sinus of equal width and 

 depth. Orbits with three denticles of approximately equal size between 

 the more prominent preorbital and postorbital teeth. Anterolateral 

 margins quadrilobate, the first or hepatic lobe tridentate and pinched 

 off from the rest of the carapace by deep furrows; the second broader, 

 also compound, but confluent with the anterior branchial region basally; 

 the third and fourth single spines surmounted by spinules, between 

 which a subbranchial spine of equal size is clearly visible. 



Basal antennal article with two prominent external teeth and a 

 denticle at the base of the first free article; all three visible in dorsal 

 view; middle tooth curving inward at tip. Two prominent inferior 

 orbital teeth, their tips making a broad, concave arc with the two 



