234 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



two light bands near tip; mature primaries blackish brown except where 

 covered by encrusting bryozoa or other organisms ; collar very low, verona 

 brown; primary spines of oral surface light colored, those around the 

 actinostome may be nearly white. The holotype is 26 mm h. d., 13 mm 

 V. d. ; longest primaries 35 mm with a diameter near base of nearly 3 mm ; 

 at tip, not quite two. 



Besides the holotype, there are two other Cidarids that must be re- 

 ferred to this species, as they agree in all essentials. One is nearly as large 

 as the holotype but is badly damaged on one side. The primaries of the oral 

 surface show more red in their coloration and the secondaries are a lighter 

 shade of brown. This specimen was taken with the holotype at Velero 

 Station 948-39. March 28, 1939, off Medidor Island, Bahia Honda, 

 Panama, in 30-35 fms on a bottom of mud, rocks and corallines, in com- 

 pany with large numbers of perplexa. A third specimen, 15 mm in diameter 

 with primaries 20-26 mm long, is supposed to be from Station 575-36, in 

 the Gulf of California, but there is some doubt as to the reliability of the 

 label. It is unquestionably conspecific with the specimens from Bahia 

 Honda but shows much more red in the coloration and the primaries are 

 not so black as in the holotype. The relationship of this species to perplexa 

 is obvious, but to refer these specimens to that species would evidently be 

 quite wrong. 



Type. — Holotype, AHF no. 46, 1 paratype. 



Type locality.— '^tzt.ion 948-39, of? Medidor Island, Bahia Honda. 

 Panama, 30-35 fms, March 28, 1939. 



Distribution. — Type locality and the Gulf of California ( ?). 



Depth.— i(}-\00 ims (?). 



Specimens examined. — ^The type, paratype and one other specimen, 

 from 2 stations. 



Gentrocidaris Doederleini (A. Agassiz) 



Plate 38, Fi^. 7 

 Goniocidaris Doederleini A. Agassiz, 1898, p. 73. 

 Gentrocidaris Doederleini A. Agassiz, 1904, p. 33, pi. 14, figs. 1, 2. 



Apparently this is a verj^ rare urchin for, in all her collecting, the 

 Velero has met with but one specimen — a small adult taken in the Galapa- 

 gos Islands, near Barrington Island, in 48-73 fms. It is 24 mm in diameter 

 and 13 mm high. The primaries are 20-28 mm long, exceedingly slender, 

 and nearly cylindrical, either smooth or with low, well separated ridges. 

 The abactinal system shows a star-like pattern, as in Hesperocidaris asteris- 

 cus but in Gentrocidaris the lines are dark brown with light brown plates 

 instead of the reverse. 



