400 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Color in life: Female pinkish olive with manus and dactyls of cheliped 

 pink. (Crane) 



Habitat: Yellow mud ; sand and broken shell ; fine gray sand. (Rath- 

 bun) Mud; coarse sand with weed. (Crane) Sandy, weedy bottom. 

 (Schmitt) Of the 33 stations of the Velero III and IV, 11 were rocky 

 bottom, 1 1 sandy bottom, 5 muddy bottom, and 6 nullipore, coral, or 

 coralline bottom. In two cases nullipores were present with the rock, 

 and shell was present with the sand. 



Depth: 5-50 fathoms. In contrast to Microphrys triangulatus, not 

 collected intertidally. 



Size and sex: The present series contains young from 4.8 mm, males 

 from 3.6 to 15.8 mm, females from 5.0 to 13.6 mm, ovigerous females 

 from 7.1 to 11.7 mm. The smallest breeding females are from Acapulco, 

 Mexico ; the largest are from Cocos Island, Costa Rica. 



Breeding: Ovigerous females were encountered off the west coast of 

 Lower California in February, in the Gulf of California in March, at 

 Cocos Island, Costa Rica, in January, and in Mexico in February. 



Remarks: An 1 1 mm male from Dewey Channel, west coast of Lower 

 California, and one of a series of eight, is the most distinctive Micro- 

 phrys branchialis of many seen. The carapace is elongated, the lateral 

 spine slender and strong, and the branchial swellings anteriorly sited. 

 The rostral, antennal, and preorbital spines are long. The tubercles of 

 the carapace are distinct, particularly the row of five across the gastric 

 region. The basal antennal article, when viewed ventrally, is seen to 

 have three spines, the first outstanding. Specimens from the west coast 

 of Lower California are regarded as typical. 



The distribution of Microphrys branchialis continues to be coastal, 

 avoiding the Mexican islands of Isabel and Tres Marias, where M. 

 triangulatus is found, and continuing from Tenacatita Bay southward, 

 including the offshore islands of Cocos, Costa Rica, and La Plata, Ecua- 

 dor. The extension of range of a species previously known only from 

 the Lower California-Gulf of California region to include all of the 

 Panamic province as herein defined, i. e., Magdalena Bay, Lower Cali- 

 fornia, to Punta Santa Elena, Ecuador, strongly substantiates its desig- 

 nation by Rathbun (1925) as the Pacific analogue of M. interruptus 

 of the Caribbean. 



The occurrence of Microphrys branchialis in the Gulf of California 

 is indubitable, records from Guaymas by Rathbun and Arena Bank by 

 Crane being supported by Velero III material from Angeles Bay and 

 Agua Verde Bay. The common Microphrys of the Gulf, however, is 



