OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 89 



cave. The adoral plates are large, much elongated, and broadened 

 as far as the median interradial line along which they are broadly 

 united with their neighbors; they taper to the level of the mouth 

 tentacle pores, then broaden again in their distal parts and pass 

 around the mouth shield, forming a lobe which separates this -shield 

 from the first side arm plate. The oral plates are triangular and 

 high. The lateral mouth papillae are numerous, and there may be as 

 many as eight or nine of them; they are conical, elongated, and 

 pointed; the unpaired terminal papilla is a little longer than those 

 on either side. These papillae are continued along the internal bor- 

 der of the large mouth tentacle pore to the number of at least six 

 on this border; the}- are unfortunately more or less poorly pre- 

 served. They disappear before the distal extremity of the pore, and 

 apparently are not continued on its radial border. 



The arms are rather flattened, and their dorsal surface is only 

 slightly convex. The upper arm plates are of medium dimensions, 

 as the side arm plates extend rather broadly over the dorsal surface 

 of the arms. These plates are triangular, almost as long as broad, 

 with a proximal angle which is sharp, though rounded at the tip, 

 and a convex distal border which is often divided into two small 

 sides united by an obtuse angle. They are separated from each other 

 from the base of the arms outward by an interval which is always 

 very narrow. 



The first under arm plate is longer than broad, triangular in 

 general form, but with the base ordinarily divided into two short 

 sides passing into each other by an obtuse angle ; the lateral borders 

 are excavated by the large mouth tentacle pores, and the distal sum- 

 mit is truncated. The second plate is already separated from the 

 first by the side arm plates, and it is the same for all the following 

 plates. These are very narrow in their proximal portion, that is, 

 in about the first two-thirds of their length, while they are much 

 broadened in their distal third. They have a sharp proximal angle 

 and two lateral borders, strongly excavated by the corresponding 

 tentacle pores, which pass over very rounded angles to form the dis- 

 tal border; this is extremely broadened and shows in the center a 

 small notch. 



The side arm plates do not project at all, and they cover a rather 

 large portion of the dorsal and ventral surfaces of the arms. They 

 carry on the first segment six subequal spines of which the length 

 is a little greater than that of the segment. These spines are cylin- 

 drical with the point rounded; their surface is rugose, and even 

 sometimes slightly echinulated. They are very close to each other, 

 and are appressed against the lateral surface of the arms; but the 

 two lateral series are very far apart in the median dorsal lines. 



