STAEFISHES OF THE PHILIPPINE SEAS. 199 



constant in occurrence. There are very few, or none, in some of the 

 areas in small specimens (station 5388), while one or more areas will 

 have at least a few developed. 



In the large specimen from station 5122 the dorsal muscle of each 

 side sends 2 very inconspicuous tendons to join the upper and outer 

 end of the twelfth and thirteenth ambulacral ossicles. It is conse- 

 quently inaccurate to state that the muscle is not attached to the 

 ambulacral ossicles in CheAraster. There is, however, no specialized 

 knob as in Luidiaster dawsoni. My key (1911<i, p. 120) should read 

 " ambulacral ossicle without specialized crest for attachment of ten- 

 don of dorsal muscles; tendons very inconspicuous." In the speci- 

 mens of Ch. snyderi and Ch. inops which I examined for this fea- 

 ture, the tendons can not be seen, possibly because the specimens were 

 partly dried. Drying does not destroy the tendon in Luidiaster, nor 

 in typical Pectinaster. 



Variations. — The principal variations have already been noted. 

 Special mention should be made of specimens from station 5388, 

 which have very numerous pedicellariae, especially on the abactinal 

 surface. These abactinal pedicellariae, however, are very variable 

 in number. There are 8 or 9 furrow spines, a trifle broadened at the 

 tip, which may be rounded or truncate. The first plate has 2 sub- 

 ambulacrals, the others have 1, until the outer part of the ray is 

 reached, when there are usually 2, the smaller being next to the fur- 

 row series. The marginal mouth spines are 8 and the inner is much 

 enlarged, jQattened, broader at the truncate tip than at base. The 

 second spine is a little shorter, and about three-fourths the length of 

 the inner. The remaining 6 are subequal, two-thirds to three-fourths 

 as long as the second oral spine, and very similar in every way to the 

 first adambulacral furrow series, though sometimes individually a 

 trifle broader. The inferomarginal and superomarginal spines are 

 markedly longer than in Ch. snyderi of nearly equal size. In these 

 specimens the papularia are much larger than in snydeH, extend- 

 ing to the end of the fifth or middle of the sixth superomarginal 

 plate. The papulae are about 40 to 45 in these small specimens. 



Type-locality.— L^t. 18° 5' 2'' S.; long. 116° 3' 8" E. (off north- 

 western Australia), 195 fathoms, gray mud. 



Distribution. — Northwestern Australia; Mindoro and southern 

 Luzon, 195 to 256 fathoms, bottom temperature 51.4° to 53.3° F. 



/Specimens examined. — One hundred and eleven from the follow- 

 ing stations : 



5122. East coast of Mindoro (vincinity Malabrigo Light), 220 

 fathoms, green mud ; 9 specimens. 



5388. Between Burias and Luzon (vicinity Bagatao Island Light) ^ 

 226 fathoms, soft green mud, bottom temperature 51.4° F. ; 99 speci- 

 mens. 



