552 ECHINOLAMPAS HELLEI. 



Echinolampas Hellei 



Echinolampas Richardi (Desml.), 1837 Tab. Syn., p. 310. (non Desmt.) 

 ! Echinolampas Hellei Yai... 1S09, in Peru. Pedic, p. 170. 



PI XV. f. 5-11; Pi XV". f. 5-6. 



This species is readily distinguished from its Indian congener by the more 

 central position of the apical system, t he greater equality in the development 

 of the anterior and posterior poriferous zones ol* each petal, the close ar- 

 rangement of the pores of the narrow poriferous /.ones, the great size of the 

 apical system, and more distant tuberculation. The test is depressed, and 

 the outline from above quite angular, rounded anteriorly, and slightly trun- 

 cated posteriorly, somewhat resembling, at first glance, species of Clypeus. 

 Alcoholic specimens in the Jardin des Plantes show that the spines are short 

 and of uniform size, of a dark violet color, — brown, according to Desmoulins. 

 Actinal surface concave ; edges of lest swollen, sloping towards the aetino- 

 stome. Phyllodes and bourrelets very prominently developed, when com- 

 pared with those of several other fossil species of the genus. The anus in all 

 species of Echinolampas is inframarginal, flush with the actinal surface of the 

 test ; anterior edge of anal system slightly curved in ; tuberculation closest 

 immediately at the ambitus ; somewhat less close, hut uniform over the 

 actinal surface, and gradually more distant towards the actinostome. 



Considerable confusion has arisen, in the discrimination of this species, from 

 its identification with a fossil species by Desmoulins; he. however, subse- 

 quently separated them, and lately has given an excellent figure of the 

 African Echinolampas in the Actes de la Soc. Linn, de Bordeaux. 



1 have figured, in PI. XV. f. 7, the anal system of this species of Echi- 

 nolampas ; the general mode of arrangement differs materially from that 

 of Rhynchopygus. There is one large anterior row of four plates, covering 

 almost the -whole membrane, with large tubercles ; the rest of the membrane 

 is strengthened by carrying from six to seven minute plates, in the centre of 

 which is situated, near the posterior edge, the small, elliptical anal opening. 



It is barely possible that this species and E. depressa may prove identical; 

 we have unfortunately only specimens of such different size existing in our 

 collections that no direct comparison can be made. The principal differ- 

 ences noticed in the ambulacral system may be only due to changes occur- 

 ring during growth. 



T)i<t Dist. Width Width 



Long. Trans. Apical .Syst. Actinost. Post. Pair Post Pair Dist. 



lli.uu. Diam. Height Ant Edge. Ant. Edge. Poril. Zone. Intrrp Hpa.i-. Post. ( Jen. 



8. 3.4 



4. 2.8 



Senegal. 



