454 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



Color in life: Not recorded. 



Habitat: Of the 21 stations from which Thyrolambrus alasselli was 

 obtained by dredging, 10 were sand bottom, with shell, nullipore, and 

 coral present in two each ; 3 were rock, with nullipore present in 2 ; 

 3 were coral, with sand present in 2 ; 2 were shell, with nullipore in one; 

 and one each were coralline, algae (weed), or nullipore alone. The 

 species was never taken on mud bottom. 



Depth : 2-35 fathoms, with one shore record from a reef. 

 Size and sex: Males are from 5.5 to 14.1 mm, females from 7.4 to 

 15.9 mm. An 8.0 mm female is ovigerous. 



Breeding: The single ovigerous female was obtained at Clarion 

 Island, Mexico, in early June. 



Remarks: Although the Askoy record (Garth, 1948) from off 

 Esmeraldas, Ecuador, is the southernmost for the species, Velero III 

 collections extend the range north from the vicinity of La Paz Bay to 

 San Marcos Island in the Gulf of California and fill in the tremendous 

 gap between Cape San Lucas and Ecuador with records from the main- 

 land of Mexico, Costa Rica, Panama, and Colombia. A portion of a 

 cheliped from Cocos Island, Costa Rica, station 108-33, is tentatively re- 

 ferred to this species, which, while found at Clarion, was not encountered 

 in the Galapagos Islands. 



That the name Thyrolambrus rathbuni De Man (1903) should be 

 changed to T. rathbunae in accordance with the recommendations of the 

 Fourteenth International Congress of Zoology (Copenhagen Decisions, 

 1953) is apparent from the author's statement of intent: "Diese niedliche, 

 kleine Krabbe, welche ich mir erlaube der eifrigen, amerikanischen Car- 

 cinologin, Miss Mary J. Rathbun in Washington zu widmen . . ." 

 This emendation, effected herewith, makes T. rathbunae Balss (1935) 

 a junior homonym of De Man's species, and as such it cannot be used 

 for the species described as T. erosus Rathbun (1898). Informed of the 

 circumstances, Dr. Balss has generously left the choice of a new name 

 to the writer, who takes pleasure in naming it for the late Steve A. 

 Glassell, whose perceptiveness in separating from a mixed series of T. 

 alasselli a then unknown parthenopid made possible the description of 

 the following species of Daldorfia. 



