142 SVEN LOVEN, ON THi: KCHINOIDEA PESCRIBED BY JINN^US. 



oacli series contiouous veiticallv, the two series, wliicli were 

 transversely contiguous in the spccimen of 24 mm., are sepa- 

 rated, slio-htlv at 40 mm., morc so at 54 mm., and rather 

 conspicuonsly at 64 mm. At the same time 



at 24 mm. the inner diameter of the scrobicule 5 a 4 is 0.71 of the plate. 



) 40 " » " '■ XX » 5 a 5 >' 0,tiö " » ' 



n .j4 » » » > » » » 5 a 5 » 0,60 » » » 



» 64 " » » " K » ■» 5 a 7 » 0,57 ' > » 



The amoiint ].\v which the total length of tlie plate ex- 

 (•eeds that of the inner diameter of the scrobicule is nearly 

 eqiially divided between the two terminal parts of the plate, 

 tliat is between the middle areola and the two raaroinal oncs 

 that börder upon the zones. 



Within the calyx of the Cidaris papillata, in the specimen 

 of 40 mm., the four costals J, ö. 4, 3 are equal and the 

 sexual pore on the oi;ter 0,.3 3 of their radial diameter; the '2, 

 madreporic, is slightly larger and has the pore in 0,;i. In the 

 specimen of 64 mm., tlie costal 1 is verv slicfhtlv laroer tlian 

 tlie J, 4, 3, and in all four the sexual pore is placed at the 

 outer 0,42 — 0,4.^ of their radial diameter, while the madreporic 

 costal 2, larger by 0,2, has the pore in 0,2.3.5. 



It follows that when the type specimen of Echinus Cida- 

 ris L. is going to be compared with another of the same spe- 

 cies hut of an inferior size, it is to be expected that in the 

 smaller specimen the middle areola of the ambulacra will be 

 found narrower and its secondarv verruculae less numerous; and 

 in the interradia: tliat the verrucae of each vertical series 

 will be less in number; that the two series will be more clo- 

 sely approximated, and thus the middle area less broad; and, 

 in the calyx, that the costals will have the sexual pore uearer 

 to their adoral maroin. 



The smallness of the interradia! primary verrucae and 

 their great number in each vertical series at once remove the 

 type of the Echinus Cidaris Jj. not only from such as the C. 

 imperialis Lamck., the C. dubia Al. Ag. or the C. papillata 

 Leske, but also from nearly every other known species of the 

 genus, derivcd from localities somehow explored at the time 

 of LiNN^us. In those characters only one among recent spe- 

 cies ao-rees with it, the (adaris baculosa Lamck. Of this a 

 specimen, of the well known typical form with purple spöts 

 on the necks of its spines, now lies before me. It has a dia- 



