THE CRINOID GENUS EUDIOCRINUS, WITH DESCRIP- 
TION OF A NEW SPECIES. | 
By Austin Hoparr Crarn, 
Of the United States Bureau of Fisheries. 
In 1868, Prof. C. Semper-described a new genus of free crinoids, 
Ophiocrinus, which differed from all other comatulids in possessing 
five undivided arms. At the same time he described the type-species, 
O. indivisus. In 1882 Dr. P. H. Carpenter renamed the genus 
EBudiocrinus (Ophiocrinus being preoccupied) and described three 
additional species, #. varians, H'. semperi, and EL’. japonicus, which 
were described in greater detail and figured in 1888. In 1883 Pro- 
fessor Perrier described /. atlanticus, and in 1894 Professor Bell 
EL. granulatus; an additional species, /’. twherculatus, was described 
by the present author during the past year. 
Among a large number of comatulids just received by the United 
States National Museum from Japan, as a deposit collection from 
Mr. Frank Springer, was a very singular specimen with but five 
arms, entirely different from the species of “Hudiocrinus” (sensu 
P. H. Carpenter), atlanticus, varians, tuberculatus, and japonicus, 
with which I was personally acquainted. It was obviously closely 
allied to the Japanese species of Zygometra, Z. hartlaubi, Z. rubro- 
flava, and Z. kawhlert, the chief difference being the possession of only 
five arms. Evidently, then, it could not be congeneric with the species 
of “Hudiocrinus,” which I had previously studied. This led to a re- 
view of the whole matter. 
The type-species of Hudiocrinus (2. indivisus) is described as fol- 
lows: 
Sechzehn Ranken stehen in einfacher Reihe um den flachen kleinen Knopf. 
Rankenglieder 18-20, sehr knotig, namentlich am Ursprung, die Verdickung ent- 
spricht den Gelenken ; die zwei ersten Glieder niedrig, so hoch als breit, das 3te 
bis 6te die langsten, doppelt so lang als breit. Die letzten Glieder schwach com- 
primirt, glatt, das letzte hat ausser dem Hndhaken einen starken Zahn. 
Das erst Glied der direkt von Kelchknopfe entspringenden Arme trigt gleich 
eine Pinnula und hat ein Syzygium ; das zweite ist ohne Pinnula; das dritte triigt 
eine solehe und das vierte hat eine Pinnula und zugleich ein Syzygium. Nun 
PROCEEDINGS U.S. NATIONAL Museum, VoL. XXXIV—No. 1613. 
Ml 
