OPHIURANS OF UNITED STATES NATIONAL MUSEUM. 129 



OQ the last dorsal spine which is more pointed than the others; their surface is very 

 rough and it even offers very small and dense denticulations which are somewhat 

 unequal. The brachial spines stand perpendicular to the longitudinal axis of 

 the arm, and they do not lie at all on the lateral plates. 



The single tentacular scale is small, conical, with a blunt point; it is often 

 hidden under the first ventral spine. The examples in alcohol are brownish-yellow. 



Connections and differences. Owing to the arms being rolled up in a vertical 

 plane, and to their being inserted under the upper face of the disk, owing also to 

 several other characters, this species evidently belongs to the genus Ophiochondrus, 

 as it has been restricted by Verrill, and from which must be excluded 0. sguamosus, 

 which forms the type of the genus OphiochondreUa. The new species which I have 

 just described will easily be distinguished from the already known species by the 

 following characters: 0. convolutus Lyman possesses six spines and the disk is 

 covered with numerous granules, which are very small and dense. 0. crassispinus 

 Lyman also has its disk covered with very small granules, the radial shields are 

 very large, and the spines amount to seven or eight. 0. gratilis Verrill is a small 

 species, the diameter of the disk of which does not exceed 3 mm.; the characters of 

 the upper face of the disk are unknown, but the brachial spines amount to eight. 

 Lastly 0. stelliger Lyman has its disk covered with minute granules, and the brachial 

 spines amount to four only. 



Among the Ophiurans gathered by the Princesse Alice, I described under the 

 name of Ophioplus armatus (07, p. 46, and 09, p. 203) an Ophiuran which was 

 represented by two specimens only and which I have found again among the forms 

 dredged by the Albatross. After a review of that species by the examination of more 

 numerous specimens and a comparison with Ophiochondrus granulatus, it seems to 

 me more correct to classify this Ophiuran also in the genus Ophiochondrus. I was 

 tempted to place it in the genus Ophioplus owing chiefly to the state of the 

 upper brachial plates, which are divided up, but it may be seen by the description of 

 0. granulatus that this character may appear also in the genus Ophiochondrus. 

 Moreover, the shape of the genital slits excludes from the genus Ophioplus the 

 species from the Princesse Alice. Now the 0. granulatus which I have just described 

 is very closely allied with 0. armatus; I shall discuss the differences which separate 

 these two species, after having described the specimens of 0. armatus gathered 

 by the Albatross. 



OPHIOCHONDRUS ARMATUS (Koehler). 



Plate 14, figs. 2-3, 6. 

 Ophioplus armatus KCEHLER (09), p. 203, pi. 38, figs. 7, 8. 



Albatross station 2415. Apr. 1, 1885. Lat. 30 44' N.; long. 79 26' W.; 

 440 fathoms; co. crs. s. sh. for.; temp. 45.6 F. Two specimens. 



Albatross station 2645. Apr. 9, 1886. Lat. 25 46' 30" N.; long. 80 02'. W; 

 157 fathoms; gn. s.; temp. 43.4 F. Two specimens. 



Albatross station 2663. May 4, 1886. Lat. 29 39' N.; long. 79 49' W.; 

 421 fathoms; br. s.; temp. 42.7 F. One specimen. 



