432 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



specimens obtained at San Gabriel Bay of Espiritu Santo Island, in the 

 southern part of the Gulf. Specimens from Clarion Island and Socorro 

 Island have the spines truncated or less upstanding, while Costa Rican 

 and Panamanian specimens are obscurely spined, the spines being little 

 more than granules for which one must search among fringing hairs. 

 Specimens from Port [Puerto] Utria are completely smooth, a condition 

 which carries the cline for spinulation to its opposite extremity. 



2. Erosion of the merus of the cheliped: Crane (1947, p. 72) found 

 the outer row of pits on the arm completely developed only in the 

 largest males of Thoe sulcata sulcata ; in smaller males and in females 

 only two or three of the outer excavations were present and these were 

 confined to the distal part of the arm. In a series of T. s. panamensis 

 from Nicaragua she found the pits so well developed that the specimens 

 might have been referred to T. s. sulcata were it not for the weak spinu- 

 lation of the meri of the ambulatory legs, while in a series from Port 

 Parker, Costa Rica, the pits were so variable as to be taxonomically 

 useless. 



3. Denticulation of the dactylus of the male cheliped : Since this 

 character is exhibited only in the largest and most mature males, and 

 since not more than half a dozen of these occur in the Hancock collec- 

 tion, it is not possible to say that a cline for this character exists also. 

 However, the bicuspid digital tooth of several Bay of Panama specimens, 

 a condition intermediate between the cylindrical simple tooth of Thoe 

 sulcata sulcata and the broad tricuspid tooth of T. s. panamensis, 

 strongly suggests this possibility. Worthy of note in this connection is 

 an overdeveloped male from San Francisco Island, Gulf of California, 

 in which the gape is as exaggerated as that shown in Bell's figure of 

 T. erosa, the dactylar tooth, however, remaining simple. 



Family PARTHENOPIDAE 



Parthenopidae Alcock, 1895, p. 257. Borradaile, 1907, p. 480. Rathbun, 

 1925, p. 510. Flipse, 1930, p. 3. 



Eyes usually retractile within small circular well-defined orbits ; 

 floor of orbit nearly continued to the front, leaving a hiatus usually 

 filled by the second [article] of the antennary peduncle. Basal antennal 

 [article] small, and deeply imbedded between the inner angle of the 

 orbit and the antennulary fossae. Antennules folding a little obliquely. 

 (Alcock) 



