OPHIUBANS OF UNITED STATES NATIONAL MUSEUM. 127 



The lateral plates, which are very broad, carry each four spines, which are 

 thin, pointed, flattened, transparent, and provided over their whole length with 

 fairly strong denticulations ; their length increases from the first ventral spine, 

 which is equal to one and a half articles, to the third one, which is equal to two 

 articles; the last dorsal spine is a little smaller. 



The tentacular pores are large, oval, and transversely widened; there is no 

 tentacular scale. 



Connections and differences. 0. guadrispinosa is allied chiefly to 0. Tiystricis 

 (Lyman), and it recalls more particularly the example of that species which Bell 

 represented in 1892. 1 But it is at once distinguished from it by the absence of 

 spines on the upper face of the disk out of the radial shields and by the brachial 

 spines being larger and fewer. 0. serpens (Lyman) has but three brachial spines 

 which are strongly echinulated, not much covered by the tegument, and unequal. 



By the shields on its upper face and by the small number of spines this new 

 Ophiuran very much resembles Ophiophryxus acanfldnus, which has recently been 

 described by W. K. Fisher, from a single specimen found in Japan between 94 and 

 150 fathoms; but it differs from it in the mouth pieces and, besides other things, 

 in the height of the oral plates and the development of the oral papillte, as well as 

 in the shape of the under brachial plates; it really belongs to the genus Ophwbyrsetta, 

 selected by Verrill out of the genus Ophiolyrsa. 



Family OPHIOCHONDRID^. 



OPHIOCHONDRUS GRANULATUS, new species. 

 Plate 14, figs. 1, 4-5. 



About 15 specimens, found on branches of Platycaulis danielsseni, without any 

 indication of locality. 



Type.C&i. No. 32306, U.S.N.M. 



The diameter of the disk may roach 7 mm., and in several specimens it varies 

 between 5 and 6 mm.; the others are smaller. The arms are more or less rolled 

 up in a vertical plane, and it is difficult to exactly estimate their length; it is about 

 25 mm. in some specimens, the disk of which is 5 mm. wide. 



The disk is pentagonal, more or less excavated in the interradial spaces; it is, 

 besides, excavated at the bases of the arms between the two radial shields of each 

 pair. The upper face is slightly convex and depressed in the central region while 

 the radial shields are protruding. This upper face lies on a higher level than that 

 of the bases of the arms. It is provided with plates which are covered up by a thin 

 tegument, which, however, allows the limits of the plates to be seen on the dry 

 specimens. These plates are rounded, small, subequal, somewhat imbricated, 

 chiefly near the outline of the disk. Each of them bears in its middle a large 

 cylindrical stump which is short and thick, with a rounded end armed with rather 

 strong, short, pointed and unequal spinules which extend over on the sides of the 

 stump, at the same time as they become much smaller, thus making the said sides 

 very rough. The radial shields are quite apparent; they are elongated, protruding, 



1 On the classification of Ophiurids, 1892, pi. 12, figs. 2, 3. 



