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BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



The apical system is about half the horizontal diameter of the test, 

 and is not distinctly elevated and not thickened. The oculars are in 

 part narrowly insert. Because of the danger of damaging the beau- 

 tiful appearance of the specimen it was not determined whether all 

 the oculars are insert; two of them certainly are, but a third appar- 

 ently is not. For the same reason the serial number of these oculars 

 could not be ascertained. The periproctal plates are apparently few 

 and correspondingly large. The genital pores (male) are small, rather 

 remote from the edge, and situated, on one of the plates at least, on a 

 slight elevation. The plates of the apical system are rather closely 

 covered with tubercles of various sizes. Especially there is a series of 

 tubercles along the inner edge of the genital plates which are fairly 

 large, bearing large flattened spines. The periproctal plates also each 

 carry one or two similar tubercles and spines. (Fig. 9.) 



The peristome is of about the same size as the apical system and is 

 elevated somewhat in the form of a cone. There are about 8 ambu- 



Fig. 9.— Part of apical system of Goniocidaris (Discocidaris) peltata, new 

 species. x8 



lacral plates in a series. The ambulacra scarcely join at the mouth 

 edge, thus leaving a rather free passage to the interradial plates, which 

 number about 6 and are in a fairly regular series. 



The primary spines are of an extraordinary development, recalling 

 those of Goniocidaris (Discocidaris) mikado. The basal disk is very 

 well developed, forming a large entire plate, usually only on the adap- 

 ical side; but sometimes it is also united across the adoral side of the 

 spine; in such cases it is, however, much narrower on the adoral side. 

 This disk may be repeated one or more times farther out along the 

 shaft of the spine; there is thus formed a series of disks, such as is 

 known in D. mikado. The second disk may be as complete as the 

 first, but the following are only indicated by the spinules being more 

 or less widened, while they are not wholly coalesced. Farther out the 

 spinules are simple, and at the same time more numerous, but not 

 arranged in regular series, and they gradually decrease in size toward 



