OPHIURANS OF UNITED STATES NATIONAL MUSEUM. 127 



The lateral plates, which arc very broad, carrj' each four spines, which arc 

 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 differenees. — 0. quadrispinosa is allied chiefly to 0. hystricis 

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

 represented in 1S92.' 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 arc strongly cchinulated, not much covered by the t<'gument, and unequal. 



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

 Ophiuran very much resemijles Ophiophryxus acanthinus, 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 tilings, 

 in the height of the oral plates and the development of the oral papilla;, as well a-s 

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

 selected by Verrill out of the genus Ophiohyrsa. 



Family OPHIOCHONDRID^. 



OPHIOCHONDRUS GRANULATUS, new species. 

 Plate 14, figs. 1, 4-5. 



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

 indication of locaht}^. 



Typf.— Cat. No. 32.306, U.S.N.M. 



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

 between 5 and 6 mm.; the others arc 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. Tliis upper face hes on a higher level than that 

 of the bases of the arms. It is provided mth plates which arc covered up by a thin 

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

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

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

 cylindrical stump wliich 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 

 dtump, 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, 



' On the classification of Ophiurids, 1S92, pi. 12, figs. 2, 3. 



