APOEOCIDARIS MILLEEI. 37 



Aporocidaris Milleri A. Ag. and Clark. 



Porocidaris Milleri A. Ag. 1S9S. Bull. M. C. Z., XXXII, 5, p. 74. PI. IV. 



Plate 9. 



Neither tridentate nor large globiferous pedicellarife occur in this 

 species, but small globiferous ones of very diverse sizes are abundant all 

 over the test. They have the valves short and wide though the proportions 

 vary, from those having the width .38 of the length to those in which it is 

 .75. The opening is very irregular, either with or without a lip, and there 

 may or may not be an end-tooth. The valves range in length from .32 

 to .87 mm. and the stalks are one or two times as lonff. 



The great variability of the primary radioles referred to in the previously 

 published description is remarkably illustrated by two specimens, each 10 mm. 

 in diameter, one from St. 3309, off Cocos Id., the other from St. 4717. In 

 the former, all the radioles are very slender and almost perfectly smooth, 

 while in the latter many are much stouter and are provided with longi- 

 tudinal series of stout, hooked prickles, as long as one-half the diameter 

 of the spine. 



This species was collected by the " Albatro.ss," during her trip to the 

 Eastern Pacific, in 1904, at the following stations. 



Station 4647. 4°33' S.-87'42.5' W. Bott. temp. 35.5^ 2005 fathoms. 

 Very It. gy. glob. oz. 



Station 4717. 510' S.-98^56' W. Bott. temp. 35.2^ 2153 fathoms. 

 Red br. glob. oz. diat. 



Aporocidaris fragilis A. Ag. and Clark. 



Plates 10, figs. 10-:21 ; 23, figs. o-8. 

 Of this species two specimens were collected at Station 3783. It is 

 closely allied to P. 3IiUcri. It is more flattened (PI. 23, figs. 7, .S) than that 

 species, but like it in that the miliaries and secondaries are distant and 

 the smaller spines are of uniform size, and very slender and elongate. 

 In a specimen of 20 mm. diameter there are five and five interambulacral 

 plates; the longest radicles (PI. 10, fig. Li) are 35 mm. and are compara- 

 tively stouter than in P. llilkri. They are of a whitish tint, and are 

 covered with sharp, prominent serrations. The actinal primary radioles 

 (PI. 10. fig. 7-7) ai-e curved, flattened, with longer teeth on the edges. The 

 color of the secondary spines and papilli\5 is light yellowish-brown. 



