STARFISHES OF THE PHILIPPINE SEAS. 511 



Rays rather slender, but slightly swollen at base. Costae 40-45 

 occupying more than a third of the total length of ray, but less than 

 one-half. They are irregular, compressed, and very prominent, the 

 sinuous ridge or summit being armed with comparatively coarse, 

 sharp, conical spinelets, their bases flaring, often touching. Some- 

 times there are two series of them. The costae are frequently in- 

 complete. There are numerous, microscopic pedicellariae on the 

 costae, but no bands of them between the ridges, or at any rate only 

 rudiments, but these bands occur on the outer part of the ray, be- 

 yond the region of the ridges. At the base of the ray there 

 are about C lateral plates joined, in a series, and the first lateral 

 spine, very slender and sharp, is at about the fifth adambulacral. 

 The succeeding spines occur opposite every other adambulacral, to 

 which the plate is firmly fastened, and are very slender, increasing in ' 

 length until in the outer part of the costal region they equal in 

 length about 6 adambulacrals. 



Adambulacral plates proximally a trifle longer than wide and 



shallowly excavated toward the furrow. The formula of the arma- 



i-\- 1 . i 



ture is — ^-^ or near the disk — ,-v + 1' The aboral furrow spinelet (i) is 

 o + i + 1 1 \ / 



about as long as the plate measured in tlie middle of the actinal sur- 

 face; the large actinal spine (/) is slender and sharp and 3 times 

 the length of the plate, while the adoral actinal spine is 1^ to If the 

 length of the plate. A specimen from station 5494 has a few prox- 

 imal plates with 2 adoral actinal spines, forming with the large spine 



an oblique series of 3 ( ~^rp ) ' ^^i infrequent variation is 2 aboral 



furrow spinelets ( -—^ j • The lateral spines are thickly covered 



with a sheath of pedicellariae. while the adambulacral spines are 

 somewhat less thickly covered, and tend to be free from them on the 

 side toward furrow. 



Mouth plates with a furrow spine extending halfway across mouth 

 of furrow, and another at the aboral end of plate; a small actino- 

 stomial spinelet just mesad to the base of the former and two-thirds 

 its length ; at the outer end of plate a large suboral, pointed spine 5 

 times the length of plates, invested with a pedicellaria-covered 

 sacculus which extends half the length of the spine or more beyond 

 the end. Tube feet covered with microscopic lanceolate glands. 



Madreporic body small. The articular surface of the pair of am- 

 bulacrals of the disk, where a ray has broken off, is much broader 

 above than below, the breadth being about equal to the height, 

 measured from the radial water tube. 



(jonads and proximal adambnlaer:il plates as in generic diagnosis. 



Type.— Cat No. 37020, U.S.N.M. 



