24 



REPORT ON RADIATA AND PROTOZOA. 



By L. F. PouRTAiijs, Keeper of the Museum. 



The most valuable accessions probably ever received in this 

 department are the collections made by Mr. Agassiz, in the 

 dredging expedition of the United States Coast Survey Steamer 

 " Blake," of which fuller mention is made in his Report. It is of 

 course premature to enter into details, as the sorting has been 

 only commenced, but an idea of the size of the collection may be 

 conveyed by comparison with those which are at least partly 

 determined. The deep-sea corals, with which I have been more 

 particularly occupied, have been sorted according to locality and 

 species, so that every species from one locality is kept separate 

 from the same species of another locality, in order to trace the 

 vertical and horizontal distribution. Of these lots, for the true 

 Corals there are 471, representing from thirty to forty species. 



The Hydrocorallinae sorted in the same way form 332 lots, but 

 the number of species I am not quite prepared to state. New 

 forms are not very numerous, as the West Indian deep-sea Fauna 

 has been quite thoroughly investigated in late years, thanks to the 

 opportunities offered by the Coast Survey ; but very fine specimens 

 of some of the species obtained by the " Challenger " expedition 

 have been dredged by the " Blake," and added to our collections. 

 Of other species which we had already, a larger number of speci- 

 mens, or better-preserved ones, have enabled me to correct or 

 complete former determinations. 



The Alcyonoid Polyps are also very numerous and very fine ; and 

 I hope to be able soon to work them up, together with those of my 

 former collection, which has been returned by Professor Koelliker, 

 who much to my regret has not found time to study them. 



Among the Echinoderms, the most abundant are the Ophiuridae 

 and Astrophytidae, which, sorted on the same principle mentioned 



