& 



328 bulletin: museum of comparative zoology. 



Rays numerous, up to forty-three (Heliaster). 

 , Rays very short, free from each other for only .15-.20 of length 



H. polybrachius 

 Rays longer, free from each other .30-.40 of length . . . . H. helianthus 



Astropecten erinaceus. 



J. E. Gray, 1840. Ann. Mag. Nat. Hist., 6, p. 182. 



Plate 1, figure 1. 



Nothing is said by Gray as to either the size or color of this species. The lar 

 est specimeus I have seen have the rays about 85 mm. long, but those taken by 

 Coker do not exceed R = 75 mm. Most dry specimens are dull yellowish, more 

 or less dusky above, while the best preserved specimens in the Coker "collection 

 are uniformly deep reddish fawn color. But in life the coloration must be much 

 handsomer, for Coker's field notes show that the specimens taken at the mouth of 

 the river Tumbes were " dorsally blue, except that the spines which margin the 

 lower angles of arms are orange color in their dorsal aspect," while of the speci- 

 mens taken at Capon it is said: "Under side white in small specimens, tinted 

 orange in larger ones ; bluish at tips of arms ; above deep blue ; the spines orange, 

 those margining the arms are bright orange, while the dorsal spines are of a 

 duller shade." The change from this bright coloration to the uniform reddish fawn 

 color of the preserved specimens is very remarkable, but is of course due to the 

 preserving fluids. These specimens were " first preserved in native spirits and 

 subsequently transferred to formalin solution" (3-5% solution in sea-water). 

 Such a marked change of color shows how little dependence can be placed on the 

 color of preserved specimens not accompanied by field notes. 



This is a Panamic species, ranging from about 25° N. to 3° 30' S. lat. It 

 was first collected by Cuming at St. Elena on the coast of Ecuador, about 2° 

 S. lat., on a bottom of sandy mud in six fathoms of water. There are specimens 

 in the M. C Z. collection from Lower California and the Gulf of California. 

 Coker took three specimens at the mouth of the river Tumbes and found the spe- 

 cies abundant at Capon. Regarding its occurrence at Capon he says: "The 

 water here is very quiet, and as the tide recedes most of these starfishes . . . 

 slip away in the water, leaving, however, a very distinct impression of the form in 

 the mud ; so that when the mud-flat is exposed one may see in abundance the 

 impressions of these starfishes, but without either the animals or any mark of their 

 departure." It is probable that Dr. Coker is mistaken in supposing the starfishes 

 to have slipped away in the water. Verrill (1901, p. 36) speaks of similar im- 

 pressions made by Luidia, and he is satisfied, as he has himself told me, that the 

 impression of the starfish in the sand is made over (not under) the starfish, and is 

 caused by ciliary currents of water among the paxillae and marginal plates of the 

 dorsal surface. If undisturbed, the starfish may by a sudden quick movement be 

 captured in situ, but if disturbed by the approach of the collector, the animal 

 moves away rapidly beneath the surface of the sand, leaving the impression in the 



