114 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



ous than others. Tentacle pores on four basal joints of arm, rather 

 large, protected by one, two, or three scales. Color (dried from alco- 

 hol), light cream-color or ve*ry light yellowish-brown, with center of 

 disk sometimes very much darker. 



Locality. Albatross station 3074, off Washington, lat. 47 22' N.; 

 long. 125 48' 30" W., 877 fathoms, green mud, bottom temperature 

 36.6, 3 specimens. 



Type.Csit. No. 25606, U.S.N.M., from station 3074. 



I am not at all sure that this species will not prove to be identical 

 with glabrum Liitken and Mortensen. I have compared it with some 

 of their specimens and find it easy to distinguish the two species by 

 the differences in the arm spines and in the upper and under arm 

 plates. Thus glabrum has seven to eleven arm spines, small triangular 

 upper arm plates and more or less pentagonal under arm plates, while 

 multispinum has twelve to sixteen arm spines, larger, more elongated, 

 diamond-shaped upper arm plates and (except the basal ones, which 

 are much broader than long) the under arm plates are triangular. On 

 the other hand, the largest glabrum was 32 mm. across the disk while 

 the smallest multispinum is 33 mm., so I do not feel satisfied as to 

 these differences being of specific value. 



Family AMPHIURIM}. 



OPHIAMBIX ACULEATUS. 



Ophiambix aculeatus LYMAN, Anniversary Mem. Boston Soc. Nat. Hist., 1880, 

 p. 11. 



Locality. Albatross station 4928, in Colnett Strait, lat. 29 51' N.; 

 long. 131 2' 30" E., 1,008 fathoms, gray sand, globigerina, bottom 

 temperature 36.8, 1 specimen. 



It is a matter for great regret that a single specimen, 5 mm. across 

 the disk, is all the material which the collection affords of this inter- 

 esting and important genus. I know of no ophiuran which gives as 

 much promise of throwing light on the relation of brittle-stars to star- 

 fishes as does Ophiambix. Seen from above the resemblance to a star- 

 fish is most striking, while the huge tentacles and tentacle pores and 

 the simple mouth parts give to the oral surface a very suggestive 

 appearance. It is rather curious that Lyman makes no reference to 

 the asteroid resemblances of this genus. To judge from the posi- 

 tion assigned it in the Challenger report, he seems to have considered 

 it allied to OpJiioscolex. Meissner a considers it nearer OpTiiopTiolis. 

 My own opinion is that its real position is very doubtful, and that we 

 shall not understand its relationships until more abundant material 

 shall make possible a complete study of its structure. For the pres- 

 ent it may as well stand at the beginning of the family Amphiuridae 

 as anywhere else. 



oBronn's Thierreichs, vol. 2, pt. 3, p. 927. 



