OPHIUBANS OF THE PHILIPPINE AND ADJACENT WATERS. 197 



which are very large, elongated, and about four times as long as 

 broad, with the long borders almost parallel, an almost straight dis- 

 tal border, and a more or less marked proximal angle. The two 

 shields of each pair are very slightly divergent, in contact distally, 

 and proximally separated bj r an extremely narrow triangular space 

 covered with small plates. Outside of each shield there is a band 

 formed of small, closely crowded, and imbricated plates ; these bands, 

 which at first are very narrow, toward the distal extremity of the 

 shield gradually broaden toward the proximal angle, which they 

 widely exceed, without, however, reaching the central region of the 

 disk, which remains naked. 



A rather large number of these plates carry a small, elongated, 

 stout, conical, and pointed spine which is inserted on the plate by a 

 broadened base. The interradial spaces are naked, but sometimes 

 there may be observed here and there a few small isolated plates, each 

 of which carries a spine identical with the preceding. The central 

 region of the disk is entirely without plates. Altogether, the arrange- 

 ment of the dorsal plates of the disk and of the radial shields, as well 

 as the disposition of the regions which remain uncovered, recalls 

 exactly the features which have heretofore served to characterize the 

 old genus Ophionephthys. 



The ventral surface of the disk is absolutely naked. The genital 

 slits are rather broad; they are provided on their internal border 

 with a row of rather broad plates which assist in narrowing the naked 

 portion of the ventral surface. 



The mouth shields are rather large, lozenge-shaped, almost as long 

 as broad, with an obtuse proximal angle bounded by very slightly 

 convex sides ; the two lateral borders, on the other hand, are slightly 

 concave, and the distal angle is thick and rounded, and forms a lobe 

 which projects into the interradial space. The rather small adoral 

 plates have the form of a crescent, and they are not in contact in the 

 median interradial line; they are rather elongated and maintain 

 almost the same width over their whole length. The oral plates are 

 elongated, two and a half times as high as broad; they are each 

 terminated by a stout, thick, short, and conical papilla, which is 

 almost as long as broad. A second papilla is found beyond the first, 

 but on a higher level, and it develops along the oral plate and termi- 

 nates in a slender and pointed tip. The outermost papilla, which is 

 inserted both on the oral and on the adoral plate, arises on the radial 

 border of the second mouth tentacle pore ; it is rather thick, cylindri- 

 cal, and short, and its tip is rounded. 



The upper arm plates of the first arm segments are almost oval, 

 a little longer than broad, and a rather small; these plates then 

 broaden little by little, becoming as long as broad, or even a little 



