NEOLAMPAS ROSTELLATA. 45 



in two specimens, one of which measured probably 7-8 mm. in length, the 

 other from 10 to 11 mm. The interambulacral spines of the bourrelets are 

 slender and longer than those of the tubercles of corresponding size in other 

 parte of the test The somewhal distanl primary radioles, are short, sharp, 

 Blender, and the intertubercular space of the whole tesl is thickly covered by 

 secondary tubercles, carrying small, slender, straighl radioles, usually having 

 a Blighl cup-shaped extremity, which have hem well figured by Thomson in 

 the Echini of the Porcupine Expedition; he has also figured the pedicellariaa 

 characteristic of this species. The principal large pedicellariae arc more 

 closely allied by their structure to the Clypeastroid than to the Spatangoid 

 types; in addition to these, there are also in the ambulacra! areas more 

 numerous pedicellariae with shorl stout stems, quite similar to the secondary 

 radioles but somewhal more slender, carrying a small trifid head sel closely 

 upon the cup-shaped extremity of the stalk. .Minute long-stemmed, small- 

 headed pedicellariae arc found near the actinostome in the ambulacral and 

 interambulacral areas. 



A- the tesl increases in size its outline becomes more angular, the posterior 

 extremity more elevated, and the Spatangoid features of the genus more ap- 

 parent. There is. however, even in the largesl specimen collected, no trace 

 of petaloid ambulacra on the abactinal surface; the ambulacra retain as far 

 as we know their simple embryonic structure. The apical system is compact, 

 the genital openings are large, the lefl anterior and posterior genitals are 

 atrophied. This was not the case either in the specimens collected by 

 Thomson or in those previously dredged off Florida, in which the left 

 anterior genital pore was wanting, in addition to the odd posterior one. In 

 a specimen measuring 10 mm. in length there are two or three madreporic 

 openings in the space between the genital openings. In Thomson's speci- 

 mens, which are larger than any 1 have dredged, there are two such 



openings. I was unable to distinguish the line of sutures between the 



different genital plates. When covered with spines, the genital openings 

 arc protected by long secondary spine-, and genital luhes are seen to 



projeci through the large openings be} I the level of the spines. Two 



or three, and sometimes four, Bphseridia are found near the actinostome 



in each ambulacral area. 



