PART 1 GARTH : PACIFIC OXYRHYNCH A 171 



Measurements: Male specimen: length 10.3 mm, width including 

 teeth 9.8 mm, without teeth 8.5 mm, rostrum 0.8 mm, width 1.6 mm, 

 cheliped 13.1 mm, chela 6.4 mm, dactyl 2.6 mm, height of palm 2.1 



mm, ambulatory legs 9.5, 9.0, , and (ca.) 6.5 mm, respectively. 



Female specimen: length 10.3 mm, width 8.9 mm. 



Color in life: The general color is brown; the feet with alternate 

 rings of reddish and brown. (Bell) 



Habitat: Sandy mud. (Bell) Velero III specimens were dredged 

 once from sand and once from rock bottom. 



Depth: Shore to 20 fathoms. 



Size and sex: Males in the present series are from 6.4 to 10.3 mm, 

 females from 6.5 to 8.3 mm; the ovigerous specimen is 7.2 mm. The 

 largest specimen on record is the 16.7 mm male reported by Rathbun 

 (1925) from the Galapagos Islands. 



Breeding: The single ovigerous female was encountered in Panama 

 in January. 



Remarks: The remarks of Rathbun (1925, p. 361) on a male from 

 the Galapagos Islands in the Paris Museum are enlightening. If the 

 specimen examined was indeed the same as that figured by A. Milne 

 Edwards, as seems highly probable, then Bell's figure of the female type 

 may be considered no more accurate than his figures have proven to be 

 in the case of species now represented in collections by adequate material. 

 In view of the great strides made in scientific illustration between 1836 

 and 1875 and the greater reliability which may be placed on A. Milne 

 Edwards's figures, this explanation seems more plausible to the writer 

 than Rathbun's, which was that the differences observable between the 

 two illustrations could be attributed to the accentuation of sexual differ- 

 ences. 



Of the characters illustrated by A. Milne Edwards's figured male, the 

 following are exhibited by Hancock expeditions males from Panama: the 

 outer margins of the orbits converge anteriorly ; marginal teeth two and 

 three are joined at their bases; teeth two and five are reduced in size; 

 the inner orbital tooth is more advanced than the outer, the front more 

 than either; the tubercles of the carapace are relatively few in number 

 (as compared with Pitho picteti) and less upstanding; the chelipeds are 

 much longer than the first pair of walking legs, the chelae swollen and 

 compressed. 



