188 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



individuals. It ranges throughout the East Indian region, north to Anima 

 Oshima in the Liu-kiu Islands and southward along the east coast of Australia; 

 it has been reported from as far west as Mauritius and Zanzibar, and as far east 

 as the Fiji, Samoan, and Hawaiian Islands. Its occurrence in the latter group 

 seems doubtful, as it was not represented in the very extensive collections made 

 by the " Albatross " in 1903. Although ordinarily a littoral form, a specimen 

 from a depth of 547 fths. is reported by de Meijere (:04). 



Phyllacanthus imperialis. 



Cidarites imperialis Lamarck, 1816, Anim. s. Vert., 3, p. 54. 

 Phyllacanthus imperialis Brandt, 1835, Prodrome, p. 268. 



Plate If, figs. 3,6, 7, K«v. Ech., A. Agassiz, 1873. Plate 58, figs. 3,4, Semon's 



gesani. Ech., Doderlein, 1903. 



This is another well-known species, dark brown or purple in color, and of large 

 size (up to 75 mm. h. d). Some or all of the primary spines frequently have 

 two or more narrow rings of light color near the distal end. The geographical 

 range of this species is from the Red Sea and Zanzibar to and throughout the 

 East Indies and alons? the east coast of Australia. I am in doubt as to whether 

 the varieties recognized by Doderlein are really sufficiently constant to be worthy 

 of names. 



Phyllacanthus thomasii. 



Phyllacanthus Thomasii A. Agassiz and Clark, 1907, Haw. Pac. Ech. : Cid., p. 15. 



Plates 37-30, Haw. Pac. Ech. Cid., A. Agassiz and Clark, 1907. 



This handsome species reaches as large a size as the preceding, and the long, 

 tapering, stout spines give it a very characteristic appearance. In the largest 

 specimens the small spines and test are dark reddish-brown, but in specimens 

 .30-.40 mm. h. d., the ambulacra and their spines are very pale brown, in sharp 

 contrast to the interambulacra and abactinal system. At all ages the primary 

 spines are salmon-colored, thickly spotted with white, and having a brown collar, 

 but in old specimens they are more or less encrusted with foreign material which 

 conceals the true color, and the collar is much wider and darker than in the 

 young. This species is known only from the vicinity of the Hawaiian Islands. 



Phyllacanthus annulifera. 



Cidarites annulifera Lamarck, 1816, Anim. s. Vert., 3, p. 57. 

 Phyllacanthus annulifera A. Agassiz, 1872, Rev. Ech., pt. 1, p. 150. 



Plate 58, figs. 5-11, Semon's gesam. Ech., Doderlein, 1903. 



This species has been so persistently confused, on the one hand with the much 

 rarer Stephanocidaris bispinosa (q. v.), and on the other with an East Indian 

 variety of the much commoner Ph. baculosa, that the limits of its geographical 



