40 U.S. NATIONAL MUSEUM BULLETIN 264 



Hemipedina pulchella A. Agassiz and H. L. Clark 



Bulletin of the Museum of Comparative Zoology at Harvard, vol. 50, 

 pt. 8, p. 245, 1907. 



= Caenopedina pulchella (Agassiz and Clark)--see Mortensen's Mono- 

 graph of the Echinoidea, vol. 3, no. 1, p. 114. 



Syntypes: 



USNM 32847 (1 dry). Albatross Sta. 3991, off Kauai, Hawaii, 272-296 

 fms., June 12, 1906. 



MCZ 3910 (1 dry). Albatross Sta. 3991, see above. 



Hemiphormosoma paucispinum Mortensen 



Videnskabelige Meddelelser fradennaturhistoriskeForeningiKjoben- 

 havn, bd. 98, p. 162, 1934. 



Holotype: 



USNM E3293 (dry), Albatross sta. 5359, Sula Sea, 8°12'45"N., 120° 

 37'15"E., 2,275 fms., Jan. 9, 1909. 



Hesperaster arachnoides H. L. Clark 



Echinoderms of Australia, p. 411, pi. 27, fig. 2, 1938. 

 = Ammotrophus arachnoides (Clark)--see Mortensen's Monograph of the 

 Echinoidea, vol. 4, no. 2, p. 153. 



Holotype: 



MCZ 7196 (dry), between Freemantle and Rottnest Island, Western 

 Australia, 10-12 fms., Oct. 19, 1929. 



Hesperocidaris houstoniana A. H. Clark 



Smithsonian Miscellaneous Collection, vol. 98, no. 11, p. 12, 1939. 



Holotype: 



USNM E5604 (dry), Tagus Cove, Albemarle Island, Galapagos, 50 ft., 

 July 26, 1938, collected by W. L. Schmitt, Presidential Cruise 1938. 



Paratypes: 



USNM E5605 (1 dry), see above. 



USNM E5606 (3 alcohol), see above. 



Histocidaris acutispina Mortensen 



U.S. National Museum BuUetin 100, vol. 6, pt. 4, p. 248, pi. 50, figs. 

 1-2; pi. 52, fig. 2; pi. 77, fig. 4, 1927. 



Holotype: 



USNM E1275 (dry). Albatross Sta. 5495, between Leyte and Mindanao, 

 9O06'30"N., 125°00'20"E., 1,785 fms., Aug. 2, 1909. 



Histocidaris crassispina Mortensen 



Videnskabelige Meddelelser fra dennaturhistoriske ForeningiKjoben- 

 havn, bd. 85, p. 66, 1928. 



Holotype: 



MCZ 251 (dry). Challenger Sta. 1646, off Sydney, New South Wales, 

 410 fms. 



This was a syntype of Povocidaris elegans A. Agassiz (1881). 



