44G DESCRIPTIONS OF SPECIES OF HELIASTER. 



proportionate length of the free rays, and apparently also, to some ex- 

 tent at least, in the character and arrangement of the spines ; but the 

 writer depends eutirely upon Professor Verrill's description for his in- 

 formation. 



Only one lot of specimens (15523) of this species has been received. 

 It was collected by Dr. W. H. Jones, 17. S. X., at Chatham Island, one 

 of the Galapagos Islands, in 1884, and by him presented to the National 

 Museum. 



Heliaster helianthus (Lam.) Gray. 



Asterias {Heliaster) helianthus Gray, Aim. and Mag. Nat. Hist., vi, p. 179, 



1840. 

 Heliaster helianthus YevTill, TTau9. Connecticut Acad. Arts and Sci., i, part 



2, 1867-1871, pp. 289, 334, 335; Perrier, Arch. Zool. Expdr., iv, p. 351, 



1875. 



Several specimens of Heliaster in the collection, all from Ecuador and 

 Peru, have been referred by the writer to this species. They agree 

 more or less closely with one auotherin the proportionate length of the 

 free rays and in the shape and arrangement of the spines, but ditrer 

 considerably in the proi^ortiouate size of the latter. One specimen from 

 Ancon, Peru (8832), corresponds very nearly with the specimens de- 

 scribed by Professor Verrill, (loc.cit., \). 289). The number of rays is 

 35; the longer radius measures OO""™; the shorter, 58"""; the free rays 

 are from 32°*°* to 38°*™ in length. The adambulacral spines are of 

 two sizes along the outer half of the ambulacral grooves, regularly 

 alternating, one to each plate. The larger ones are long, stout, slightly 

 enlarged, and rounded at the tips; the others are not more than half as 

 long, slender, generally tapering, but seldom acute at the tips. Be- 

 tween the adambulacral spines and the first abactinal row, on each side 

 of the rays, there are never more than five regular longitudinal rows of 

 spines, generally only four, of which the two lower belong to the ventral 

 plates and are close together. The spines of the ventral series are sub- 

 equal in size and of about the same size and shape as the larger of the 

 adambulacral spines, though sometimes tapering. A third ventral row 

 is occasionally indicated toward the base of the rays by a few small 

 spines. 



The spines of the upper and lower lateral rows are somewhat smalh r 

 than the actinal and abactinal spines, and those of the median row are 

 very small when present, being usually wanting altogether. The spines 

 of the upper surface are of subequal size, rather short, stout, enlarging 

 from the base upwards, and well rounded on top. Their arrangement 

 is the same as described by Professor Verrill. They are more numerous 

 and more closely placed than in H. Gumingii and midtirailiata, but less 

 numerous, larger, and more regularly arranged than in H. microhrachia. 



One specimen, labeled simply Peru (15525), is much larger than the 

 others, the longer radius measuring about 115™'°, the shorter about 

 70°*™. There are, however, only 32 rays. The spines of the upper sur- 



