PART 1 GARTH : PACIFIC OXYRHYNCHA 259 



Color in life: Exposed parts reddish, inclining to roseate, becoming 

 yellowish white on the sides. Fingers white. (Stimpson) 



Habitat: Deeper water, but occasionally taken inshore or brought 

 up by fishermen. (Johnson and Snook) Large carapace shells of this 

 deeper water crab are commonly washed up on the beach [at Laguna]. 

 (Baker) 



Depth: To 68 fathoms, Albatross. (Rathbun, 1925) Hancock speci- 

 mens were all obtained in 23 fathoms or less. 



Size and sex: While the Hancock series is not sufficiently extensive to 

 present a continuous record of growth and development, there is a wide 

 range, from 6.7 to 190 mm, between the smallest and largest specimen. 

 The young are more slender than the adults, with the rostral, preorbital, 

 and postorbital spines more prominent. The postorbital spine is particu- 

 larly slender, acute, and equally advanced with the tip of the cornea. The 

 hepatic region is dome-shaped, a tiny papilla surmounted by a cluster of 

 hairs representing each of the two hepatic spines of the adult. Once freed 

 of its accretions of detritus, the young specimen appears almost naked, 

 the carapace being devoid of short pubescence and the longer hairs being 

 fine and inconspicuous. Sex is readily determinable in a 12.7 mm male 

 and a 12.5 mm female. No enlargement of the male cheliped is apparent 

 in specimens of 76 and 92 mm ; nor do females to 56 mm show evidence 

 of having borne ova. It is between these and the measured male of 190 

 mm and female of 114 mm, a size range not covered by the present series 

 of specimens, that secondary sex characters are developed. 



The specimen measured by Rathbun (1925, p. 199), with dimensions 

 of 200 by 159 mm, is 10 mm longer than the male measured above, which 

 was not the largest encountered by the Velero III. Several larger speci- 

 mens, kept dry for want of suitable containers, were allowed to deteri- 

 orate to powder. 



Breeding: No ovigerous females are included in the present series. 



Remarks: Although the specimen referred by Boone (1930b) to 

 Mithrax rostratus Bell has not been examined, the description and photo- 

 graph leave no doubt that it is a mature male of Stimpson's species. No 

 Mithrax is known to occur at La Jolla, where the specimen was col- 

 lected by G. P. Englehardt of the Brooklyn Museum, nor is it likely that 

 specimens of 145 mm dimension, if of a species other than commonly 

 encountered, would have been overlooked for these many years by en- 

 thusiastic collectors who regularly comb the southern California beaches. 



The young specimen obtained by the N. B. Scho field in 22 fathoms 

 at Cordell Bank (C.A.S. Locality 31180) represents a northward exten- 



