52 SVEN LOVEN, ON POURTALESIA, A OENUS OF ECniNOIDEA. 



ventil, in Sch. japonicus and Sch. gibberulus with the fifth, in Abatus cavernosus with 

 the eighth, in A. Philippii with the seventh. In Agassizia scrobicuhita and Faorina 

 chinensis they comnience with the sixth, in Hemiaster Fourneli with the seventh, in 

 Desoi"ia australis with the tenth. 



Among the Prymnodesmians perhaps the greatest number of subanal intra-fasciolar 

 pedicels occurs in the genus Brissus, they being as niany as nine on either side in 

 Brissus carinatus Al. Ag. ^), and at least five or four in Brissus Scilla3 and Brissus 

 Garretti Al. Ag. Breynia australasiaj has six in I a, seven in V b, the old Micraster 

 cor anguinum tive on either side, Plagionotus pectoralis and Kleinia luzonica four. 

 In Meoma ventricosa, Brissopsis lyrifera, Echinocardiuin cordatum, Lovenia subcarinata, 

 Maretia planulata, there are three, in Spatangus purpureus and Palajotropus Josephinas 

 only two. Among the Pryranadetes the diversity is greater, Agassizia scrobiculata 

 possessing live or six, Abatus Philippii, Desoria australis, Faoi'ina chinensis three, 

 Hemiaster Fourneli Des. as many as eight. 



A very young specimen of Brissopsis lyrifera, measuring only 4, c mm. in length, ^) 

 has the plates 6, 7, 8, 9 of \ a and V b extended within the fasciola, and the three: 

 7, 8, 9, bearing semi-penicillate pedicels, all which is as in the adult. The number 

 of intra-fasciolar pedicels, normal to each species, therefore, seems to be obtained at a 

 very early age, so that specimens, inferior in size and presenting fewer subanal intra- 

 fasciolar pores ouglit not, on that account, to be taken for juvenile stages of species 

 possessing a greatei' number of such pores, and to whicli they in otlier respects may 

 have some resemblance. At the same time, however, it is not to be overlooked that 

 the number of these pores is sometimes, but rarely, seen to vary slightly in one and 

 the same species, and that even in the same specimen there may be one more in I a 

 than in V b, or vice versa. But these are accidental variations, and, with proper care, 

 the number of subanal intra-fasciolar pedicels may be used, with perfect confidence, 

 as a speciiic character. 



Varions, with regard to size and form, as are the pedicels of tlie bivium, the 

 frontal pedicels, those of the ambulacrum III, are still more so. In this the phyllodean 

 pedicels are soon succeeded by simple pedicels. Wherever their succession is not inter- 

 rupted by a dorsal fasciola, they continue unaltered and of minute dimensions all up to 

 the calycinal system. Thus it is in Spatangus purpureus O. F. M., Maretia planulata 

 Lamk. and Maretia älta Lutken. In Maretia planulata, Fl. X,jig. 104, they taper into a 

 rounded tip, within which are seen reticular lamels. In Spatangus purpui-eus those 

 next to the phyllodean pedicels rise abruptly from a large and tumid base, while the 

 folloAving, up to the calyx, are slender and very small, and similar to the simple lateral 

 pedicels of Brissopsis, Pl. IX, jig. 83, 84, or those of Meoma, PL VIII, fig. 70, 71, 

 described above, terminating in a small disk, with highly flexible margin. In most cases 

 the dense pigment of the top prevents observing its internal structure, but, when long 

 macerated in weak spirits, it sometimes happens to retain the calcareous skeleton still 

 coherent, Pl. X, fig. 109. Then it is seen, that at the base of the flexible margin 

 ') Revision, pl. XXXI, a, fij;. 3, 4. — "-) Études p. IG, pl. XXXVII, fig. 218. 



