42 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



torn away, must have had a diameter of about 10 mm. The other 

 specimen is entire ; the diameter of the disk is 9 mm., and the arms 

 are 20 mm. long. I give here two photographs of this specimen (pi. 

 22, figs. 11, 12), as well as some photographs of isolated arm spines 

 (pi. 96, fig. 13), showing the very small ventral (a, b) and the much 

 larger dorsal (c). 



The specimens collected by the Siboga upon which I established 

 the species were dredged between latitude 6° N. and 4° S., and be- 

 tween longitude 120°-131° E. at depths varying between 350 and 

 4,239 meters (191 to 2,311 fathoms). 



Family OPHIACANTHIDAE. 



OPHIODICTYS, new genus. 



Description. — The genus Ophiodictys has certain affinities with 

 the genus Ophioplmthaca, but it is remarkable for the presence on 

 the distal border of the side arm plates of a little row of hooks, about 

 six on each plate, which appear at a short distance from the base of 

 the arm; these hooks precede the ordinary arm spines, which are 

 inserted beyond them. In the terminal portion of the arms the ordi- 

 nary spines disappear and the hooks alone persist. These hooks are 

 absolutely identical with those which exist in the Phrynophiurida of 

 Matsumoto, but the external characters of the skeleton do not permit 

 of assigning this new ophiuran to any of the known forms in that 

 order ; on the contrary, it recalls the Loemophiurida. I believe that 

 this new genus should be placed among the genera of the family 

 Ophiacanthidae, from all of which, however, it differs completely 

 through the occurrence of the hooks which I have just described. 

 It thus seems to me to form a very interesting intermediate between 

 the Phrysophiurida and the Loemophiurida. 



Type of the genus. — Ophiodictys uncinatus, new species. 



OPHIODICTYS UNCINATUS, new species. 



Plate 7, figs. 4-11. 



Locality. — Albatross station 5668; Macassar Strait; Mamuju 

 Island (E.) bearing S. 31° E., 19.64 kilometers (10.6 miles) distant 

 (lat. 2° 28' 15" S., long. 118° 49' 00" E.) ; 1,648 meters (901 

 fathoms) ; December 29, 1909 ; gy. M. 



One specimen (Cat. No. 41017, U.S.N.M.). 



Description. — The specimen is in very good condition; three arms 

 are preserved entire, the two others being broken off some distance 

 from the base. The diameter of the disk is 8 mm. ; the arms, which 

 are rather flattened, are between 45 mm. and 50 mm. long. 



The disk is rounded and the dorsal surface is flattened. It is 

 strongly concave in the interradial spaces, and each of the incisions 



