224 Bulletin American Museum of Natural History. [Vol. XXXIL 



long, was 75 mm. wide and 60 mm. high, and so was some seven per cent 

 higher than mine. But some of the fragments at hand indicate higher 

 tests than that of the whole specimen, so I do not think this difference is 

 important. The color of the test is deep reddish-purple, but this color 

 seems to be superficial and easily rubbed off leaving the bare plates purplish- 

 white. Excepting that no globiferous ones were found, the pedicellarire agree 

 well with the description and figures given by Mortensen (1. a). I agree 

 with the latter that Cystechinus cannot be distinguished from Urechinus. 

 Station 5684. Southwest from Magdalena Bay, west coast of Lower 

 California, 1760 fms. Eight (?) specimens. 



Urechinus reticulatus x sp. nov. 

 Plate XLVI, Figs. 10-13. 



Length of test, 67 mm.; breadth, 62 mm.; height, 46 mm. Color deep reddish 

 purple, but spines, pedicellariae and the surface of each plate, except around margin, 

 dull greenish-yellow. The effect of this coloration is a yellowish animal, handsomely 

 reticulated with deep purple. The plates composing the test are noticeably higher 

 in proportion to their width than in loveni, from the ambitus upward. The plates 

 of the ambulacra differ little from those of the ambulacra in either height or width. 

 Thus the antero-lateral ambulacrum is 21 mm. wide at ambitus and has 20-21 plates 

 in each column, while the antero-lateral interambulacrum is 21.5 mm. wide and 

 has 17-18 plates in each column. An ambulacral plate just above the ambitus is 

 10 mm. wide and 7 mm. high; an adjoining interambulacral plate is 9.5 mm. wide 

 and 8 mm. high. The abactinal system is somewhat distorted and obviously not 

 normal; the madreporic genital lies, as in U. loveni, directly in the long axis of the 

 animal, but there are only two genital pores, a left anterior, in a plate separate from 

 the madreporic genital, and a right posterior; the oculars are distorted and the left 

 posterior genital seems to be imperforate. The periproct is just below the ambitus, 

 on an oblique surface, and not completely actinal as in loveni. The mouth is more 

 nearly central than in loveni, lying more than two fifths of the long axis back of the 

 anterior margin, while in loveni, it is distinctly less. 



The pedicellariae are exceedingly characteristic and indicate that this species is 

 quite distinct from loveni. Four kinds of pedicellariae were found, but the globiferous 

 are very uncommon, only two being seen. The ophicephalous pedicellariae are not 

 to be distinguished certainly from those of loveni; they occur chiefly in the region 

 about the periproct. The ordinary tridentate are similar to those of loveni but are 

 at once distinguishable by the low basal portion of the valves with straight lateral 

 margins; in loveni, the base is higher and its lateral margins are angular and often 

 with a tooth at the angle. The most conspicuous pedicellariae on reticulatus are the 

 stout, tridentate, which are common around the mouth and abundant on the peri- 

 proct. The heads are very robust, the valves measuring .40 to .60 mm. long and 

 .25 to .40 mm. wide. The blade is nearly circular (i. e. as wide as it is long) but 

 otherwise the valves are much like those of naresianus as figured by Mortensen (1. c. 



1 reticulatus = with lines like the meshes of a net. 



