PART 1 GARTH : PACIFIC OXYRHYNCHA 461 



mm, manus 11.5 mm, dactylus 3.1 mm, height of palm 4.4 mm. Male 

 specimen: length 10.7 mm, width 13.7 mm, rostrum 0.7 mm, width 1.8 

 mm, cheliped 23.8 mm, merus 9.3 mm, manus 12.0 mm, dactylus 3.1 

 mm, height of palm 4.1 mm. 



Color in life: For the description of a specimen from Isabel 

 Island, Mexico, see Garth (1946, p. 413). 



Habitat: Sand bottom in 21 of 40 dredge stations, with shell present 

 in 7 and coralline, weed, or nullipore represented in 3 more; mud bot- 

 tom in 10 stations, with sand present in 6 and shell in 2 more; rock 

 bottom in 3 stations, with mud or shell present in 2 ; coralline in 3 sta- 

 tions, with nullipore in one; shell in 2 stations, with sand in one; and 

 coral in a single station. 



Depth: 1.5 to 30 fathoms. In the Galapagos, to 60 fathoms. (Garth, 

 1946) 



Size and sex: Males 4.9 to 10.7 mm, females 4.7 to 11.2 mm, ovi- 

 gerous females 8.9 to 10.3 mm, young from 3.5 mm. Specimens from 

 Colombia and Ecuador tend to run small; specimens from the Gulf of 

 California and Mexico tend to run large ; however, minimum length of 

 ovigerous females from the two extremes of range differs by only 0.1 

 mm. 



Breeding: Ovigerous females were encountered by the Velero III 

 at Socorro Island, Mexico, and at Salango Island, Ecuador, in January, 

 off Costa Rica and Panama in February, off Costa Rica and in the Gulf 

 of California in March, and in the Bay of Panama in May. 



Remarks: In view of the exceeding abundance of Solenolambrus 

 arcuatus, and the great variety of of habitats in which it has been taken, 

 not only by the Velero III but by the St. George and the Askoy as well, 

 it seems incredible that Rathbun did not have a single specimen with 

 which to illustrate the species as recently as 1925. Specimens sent to her 

 for identification prior to 1937 were returned as either Mesorhoea belli 

 (A. Milne Edwards) or Solenolambrus typicus (Stimpson), the Atlantic 

 species. The range of S. arcuatus has been extended by the Velero HI 

 from Panama to Tepoca Bay, Sonora, Mexico, on the north, and from 

 Cape Pasado, where it was taken by the Askoy, south to Cape Santa 

 Elena, Ecuador. The insular localities of Socorro and Galapagos Islands 

 have been added. 



