514 Leuckart: Bericht üb. d. wissenschaftlichen Leistungen 



the anal snout. This genns has a short but deeply sanken actinal 

 groove and a small anal pouch. 



ürechinus, A. Ag. ürechinus and Cystechinus have not the 

 sunken actinal groove with characters as the Pourtalesiae. In this 

 genera the actinostome is niore or less central, and does not differ 

 materially in its structure or position from that of the raore normal 

 Spatangoids. The structure of the ambulacra, however, is as in 

 Pourtalesiae and the other deep-water forms allied to them, quite 

 differeut from that of the Spatangoids, with which externally they 

 present many points of resemblance. ürechinus in outline and ge- 

 neral appearance resembles, at first gbnce, Neolampas, but in the 

 structure of the test it is raore closely allied to Cystechinus, having 

 like it a nearly flat actinostome and large ambulacral plates. The 

 anal System alone recalls Neolampas by its position in a shallow 

 groove placed above the ambitus. 



Cystechinus, A. Ag. This genus has the general appearance 

 of Ananchytes, with the simple ambulacral System of the Pourtale- 

 siae; actinostome much less labiate than in that group of Spatan- 

 goids. This genus and ürechinus, as well as Homolampas and 

 Palaeotropus, with the actinostome nearly in one plane, form a 

 ready ^ransition to the actinostome of the Nucleolidae and Echino- 

 lampadae by additional development of the interambulacral tubercles 

 in immediate proximity to the actinostome and their crowding to- 

 gether to form bourrelets more or less prominent, and thus pass into 

 such types as Neolampas, which have the simple ambulacra of this 

 group, with the actinostome of the Echinolampadae proper. 



Ärgopatagus, A. Ag. This genus is allied to Homolampas. 

 It has, like it, a subanal fasciole, but no lateral fasciole, a more 

 labiate actinostome. The abactinal surface is covered by distant 

 primary tubercles of uniform size both in ambulacral and interam- 

 bulacral areas. They are more numerons, but smaller, on the acti- 

 nal siirface. 



G enicopatagiis , A. Ag. This genus has striking affinities 

 with Ilolaster, Toxaster. and Cardiaster. The lateral ambulacra and 

 the odd ambulacrum have an identical structure, as in Toxaster, tho 

 ambulacra are slightly sunken, the double pores giving the ambu- 

 la(;ra above the ambitus a slight petaloid appearance, much as in 

 Paleopneustes. 



Als Rhabdocidaris recens n. sp. beschreibt Troschel 

 (Arch. für Naturgescb. 1877. Tb. I. S. J27 -134. Taf. VIII) 

 einen jetzt noch lebenden Seeigel mit gekerbten Höckern, 

 wie solche so häufig bei fossilen Arten gefunden werden. 

 Das Exemplar stammt von Singapore und unterscheidet 



