[SCIENTIFIC RESULTS OF THE PHILIPPINE CRUISE OF THE FISHERIES 

 STEAMER "ALBATROSS," 190* b.] 



PROISOCRINUS, A NEW GENUS OF RECENT CRIXOIDS. 



By Austin Hobart Clark, 



'slant Curator, Division <;/' Marim Invertebrates, I . S. National Mus> 



The work of the IT. S. Bureau of Fisheries steamer Albatross among 

 the Philippine Islands has just brought to light one of the most 

 interesting species of recent stalked crinoids yet discovered. It 

 is not certain whether the new genus which it represents should 

 be referred to the Apiocrinidas or to the Pentacrinitidas; the general 

 structure of the calyx and arm bases is that of Bathycrinus; of the 

 arms and pinnules that of the Pentacrinitidae ; of the proximal part 

 of the stem that of the Pentacrinitidae, but of most of the stem that 

 of Calamocrinus. Its resemblance to certain species of Millericrinus, 

 in particular to .1/. nodotianus, is undoubtedly more than super- 

 ficial, and it is quite possible that it should be considered as con- 

 generic with them. In general terms it may be said to hold exactly 

 the same relation to the Pentacrinitidae as Thiolliericrinus does to 

 the Comal ulida. 



The height of this new form without the root is somewhat over 

 40 inches, .so that it is much the tallest recent fixed crinoid yet dis- 

 covered. Its color is a vivid scarlet, midway between the purple or 

 green of the Pentacrinitidae and the yellow of the Apiocrinidae and 

 Bourgueticrinidae in significance. 



The new genus may be known as 



PROISOCRINUS, new gem 



The characters of this genus are included with those of the single 



species which it contains. 



Genotype. -Proisocrinus ruberrimus, new species. 



PROISOCRINUS RUBERRIMUS, new species. 



The stem is 843 mm. in length, 3 and contains Mi' columnars; 

 it is broken at the base, but was undoubtedly firmly fixed by a 

 large root, probably like that of Phrynocrinus or Calamocrinus. 



The upper part of the stem (fig. 1) is 6 mm. in diameter; it is com- 

 posed of pentalobate columnars, generally alternating in size, but 



<*The total length of the entire animal is I meter, L8 millimeti 



Proceedings U.S. National Museum, Vol.. 38— No. 1756. 



