76 PORCELLANASTERIDAE. 



named and described by him. Of the other nine species, all but one were taken 

 by the Albatross Expedition of 1891. 



Half of the deep-water species described as new belong to the Brisingidae, 

 while a fifth member of the family, in this collection, was hitherto known only 

 from the Atlantic Ocean. These facts illustrate well how characteristic of the 

 deep-water fauna the Brisingidae are and how little that fauna is as yet known. 

 It is worthy of note that of the more than a dozen species of Brisingidae now 

 known from the Pacific, not one is in the present collection. 



With the increasing knowledge of the deep-sea fauna, several genera of 

 sea-stars have been enlarged by numerous species until it is by no means easy 

 to determine the various forms assigned to them. I have therefore attempted 

 the revision of Hymenaster and Zoroaster. As the latter genus includes the 

 bulk of the Zoroasteridae, the revision is extended to include the other genera 

 and species thereof. Artificial keys to the species which seem entitled to recogni- 

 tion are included. Complete lists of the species proposed up to the present 

 time, in these genera, with the necessary bibliographical references, are also 

 given. 



SYSTEMATIC ACCOUNT. 



PORCELLANASTERIDAE. 



Eremicaster pacificus. 



Porcellanaster pacificus Ltjdwig, 1905. Mem. M. C. Z., 32, p. 89. 

 Eremicaster pacificus Fisher, 1907. Zool. Anz., 32, p. 14. 



These specimens, in which R = 15 and 22 mm., are not pecuUar in any 

 way, but agree well v^iih the original material from the Panamic region. I 

 fully agree with Fisher, in dissent from Ludwig, that the number of cribriform 

 organs is a more important, and also a more available, generic character than the 

 presence or absence of the segmental papillae. The bathymetrical range is 

 considerably increased by the present record and the geographical range is 

 extended to the south about 300 nules. 



Station 4647. Eastern Tropical Pacific, 4° 33' S., 87° 42' 30" W., 2,005 fms. Bott. temp. 35.5°. Lt. gy. 



and br. glob. oz. 

 Station 4649. Eastern Tropical Pacific, 5° 17' S., 85° 19' 30" W., 2,235 fms. Bott. temp. 35.4°. Fne. 



stky. gy. m. 



Two specimens. 



Eremicaster tenebrarius. 



Porcellanaster [Eremicaster) tenebrarius Fisheb, 1905 (10 June). Bull. U. S. Bur. Fish., 24, p. 293. 

 Porcellanaster waltharii LtTDWio, 1905 (July). Mem. M. C. Z., 32, p. 92. 

 Eremicaster tenebrarius LmjwiG, 1907. Zool. Anz., 31, p. 318. 



