60 pana:mic deep sea echini. 



Dermatodiadema globulosum A. Ag. 



Dermatodiadema globulobum A. Ag. Bull. 31. C. Z. 1898, XXXII. No. 5, p. 76, 



PI. V. figs. 3, 4, 5.1 



Plates 2-1, figs. /-?; 26, fig. ^ ; 28, figs. 3, i; 29, figs. 5-7. 



This species is readily distinguished by its high test (PL 24, fig. ^), the 

 row of large plates surrounding the anal opening (Pis. 24, figs, i, 2; 28. 

 figs. J, 4), with an outer circle of smaller irregularly arranged plates, which 

 with the large plates cover the greater part of the anal system. The anal 

 plates are covered with long slender miliary spines similar to those of the 

 ambulacral and interambulacral areas. D. globulosum is also noted- for its 

 wide ambulacral area. 



A specimen of 22 mm. in diameter was 19 mm. in height, the apical 

 system 12.5 mm. in diameter, the anal system 8 mm. in diameter, the actinal 

 system 8 mm. in diameter, the greatest width of the ambulacral system 

 3 mm., the longest radiole 40 mm. The radioles of D. globulosum are much 

 stouter than those of D. horridum and are covered with coarser verticillations. 

 There were four ambulacral plates to each interambulacral plate in the 

 equatorial region of the test. The scrobicular areas of the primary' inter- 

 ambulacral tubercles are marked for the deep furrows to which are attached 

 the muscular bundles of the base of the radioles. 



In a specimen 25 mm. in diameter there are eight primary interambula- 

 cral tubercles with a large elliptical scrobicular area connected at the sutures 

 of adjoining plates (PI. 29, fig. 6'). Closely packed miliaries cover the 

 interambulacral plates in the median space between the primaries, and 

 similar less crowded miliaries separate the scrobicular area from the ambu- 

 lacral areas. The primary tubercles are perforate, and the larger ones 

 crenulate. 



In the ambulacral area, Fig. 90, the small secondary tubercles (PI. 29, 

 figs. .'7, 7) are separated by one or two plates which carry only a few mili- 

 aries ; they occur in two irregular vertical rows, and contrast with the regu- 

 lar arrangement of the large miliaries in D. horridum. The pairs of pores 

 arc small. Fig. 91, and occupy a much smaller proportion of the ambulacral 

 plates than in D. horridum (PI. 29, figs. J, J). 



* In the •' Preliminary Report '* tliis figure was by mistake quoted as D. horridum. 



