484 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Station 5607, same locality, 761 fathoms, fine sand ; 2 specimens. 

 Station 5608, same locality, 1,089 fathoms, gray mud, bottom tem- 

 perature 36.3° ; 1 specimen. 



Genus PHOLJDASTER Sladen. 



PhoUdaster Sladen, 1889, p. 426. Type, Ph. squama tus Sladen, first spe- 

 cies; not designated. (See also 1885, p. 616, no binomial.) 



PHOLroASTER SQUAMATUS Sladen. 



PJioUdaster squamatus Sladen, 1889, p. 427, pi. 67, figs. 5 and 6; pi. 68, 

 figs. 5 and 6. 



Specimens examined. — Sixty-two from the following stations : 



Station 5212, east of Masbate Island, Philippines, 108 fathoms, 

 gray sand and mud ; bottom temperature, 59.9° F. ; 35 specimens. 



Station 5214, east of Masbate Island, 218 fathoms, green mud ; bot- 

 tom temperature, 51.4° F. ; 1 specimen. 



Station 5391, between Samar and Masbate, 118 fathoms; 1 specimen. 



Station 5392, between Samar and Masbate, 135 fathoms, green mud, 

 sand ; 13 specimens. 



Station 5393, between Samar and Masbate, 136 fathoms, hard sand ; 

 12 specimens. 



Type. — In the British Museum (Natural History). 



Type-locality. — Challenger station 204, off Tablas Island, Philip- 

 pine group (lat. 12° 43' N. ; long. 122° 9' E.) 100 fathoms, green mud. 



Distrihutien. — Known from the central part of the Philippine 

 group, 100 to 135 fathoms, mud and hard sand. 



Remarks. — These specimens are from near the type-locality and 

 agree well with Sladen's description and figures cited above. There 

 are no superambulacral plates in this species. 



Genus BYTHIOLOPHUS Fisher. 



Bythiolophus Fishek, 1916&, p. 31. Type, B. acanthinus Fisher. 



Diagnosis. — In general structure i-^sembling Zoroaster, except in 

 the presence of subambulacral plates, in the specialization of the first 

 superambulacral plate as a conspicuous buttress running from the 

 body wall at the interradius to the upper end of the 2 first ambulacra! 

 ossicles, and in the arrangement of the abactinal skeleton. In this 

 the adradial series is more prominent than the carinal, consisting of 

 alternately larger and smaller, transversely elongated plates, the 

 larger of which overlie the lateral third of the carinals; both sorts 

 strongly overlap the upper end of the superomarginals. Two series 

 of marginal, and 4 series of intermediate plates. Adambulacral 

 plates as in Zoroaster. 



Remarks. — In Zoroaster the carinal plates are always larger than 

 the adradial plates. The latter are very often nearly hidden by the 



