Boone, Echinodermata; Cruises of "Eagle" and "Ara," 1921-28 135 



References: Cidaris esculentus Leske, Add. ad Klein, p. 74, 1778. 



Echinus ventricosus Lamarck, Anim. sans Vert., vol. Ill, p. 44, 1816. 



Hipponoe esculenta A. Agassiz, Mem. Mus. Comp. Zo-ol., Ill, pt. 1, p. 

 135, 1872 (with extensive synonymy) ; ibid, part II, p. 301; ibid, 

 part III, p. 501, pi. VI, figs. 28, 29, pi. Via, figs. 1-3, pi. VIII, 

 fig. 29, 1872.— H. L. Clark, Bull. U. S. Fish Comm., vol. XX, 

 part 2, p. 254, 1901. — Verrill, Trans. Conn. Acad. Arts and Sci., 

 vol. XII, p. 324, pi. 34 B, fig. 2, 1907.— D. H. Tennant, Pubi. 

 132, Carnegie Inst. Washington, p. 135, 1910; (reports use of 

 this urchin in hybridization experiments). 



Tripneustes escidentus Bell, Proc. Zool. Soc. London, p. 657, 1879. 

 — R. Rathbun, Trans. Conn. Arts and Sci., vol. V, p. 144, 

 1879. — Mortensen, Danish Ingolf Exped. Echinoidea, vol. IV,< 

 part 1, pp. 110, 112-113, 137; part II, pp. 184, 185, 186, 188, 

 189, 193, 1907. 



Tripneustes angulosus Bell, Ann. Mag. Nat. Hist., ser. 5, vol. VIII, 

 p. 437, 1881. 



Family : STRONGYLOCENTROTIDAE. 



Genus- STRONGYLOCENTROTUS Brandt. 

 Strongylocentrotus gibfoosus (Agassiz and DeSor). 



Plates 87 and 88. 



Type: The type was collected in the Galapagos Islands and is 

 deposited in the Paris Museum. 



Distribution : Panama to northern Chile, including the Galapagos 

 Islands. Littoral. 



Material examined: Six specimens, collected in shallow water, 

 Webb Cove, Albemarle Island, Galapagos Islands, March, 1928, by 

 the "Ara." 



Color: These dried specimens show the test to be reddish brown, 

 the spines olivaceous green. 



Technical description: The largest specimen of the series meas- 

 ures 43 mm. diameter, 26 mm. height. The test is thin, somewhat 

 depressed, the abactinal area rather sunken, the sidewalls regularly 

 arched, the actinal surface flattish. The actinal area is small, with 

 slight cuts. The ambulacral zones are a little elevated above and 

 slightly wider than the interambulacral zones. The poriferous zones 



