298 Dr. Sclater on Propithecus bicolor and Rhinoceros laslotis. 



rior in development to the former one. In a much earlier 

 stage (fig. 10), when the young Echinus^ 0'6 millim. in dia- 

 meter, no longer shows any remains of its pluteus, but still 

 does not present any indications either of mouth or anus, it 

 moves, as we learn from J. Mliller's investigations, by means 

 of five large primordial tentacles furnished with sucking-disks, 

 which issue, at equal distances apart, from inconsiderable de- 

 pressions not far from the margin of the ventral surface of the 

 lentiform body, which was turned towards the inside of the 

 pluteus. Within these large tentacles is situated a circle of 

 five pairs of calcareous reticulated disks, of a rounded, inter- 

 nally oblong form. Each disk has near its aboral end a 

 large, evenly bounded, oval, outwardly pointed aperture, 

 above which is placed one of the ten smaller tentacles (figs. 

 12 & 13). These five pairs of disks can hardly be any thing 

 but the foundations of the first primary ambulacral plates, and 

 the rather because, between the pairs nearer to the periphery, 

 five smaller, nearly triangular plates come in, which then 

 would be the first commencement of the interradia. Each of 

 the five large primordial tentacles has its base in the line 

 which separates each pair of the ten smaller and later ones, 

 at the point from which the median suture of the ambulacrum 

 wall subsequently start. Can these five isolated tentacles have 

 any thing in common with the tentacles of the buccal mem- 

 brane, which also first make their appearance isolatedly? 

 Krohn saw them become absorbed and disappear before the 

 mouth opened, and the ten paired tentacles become the instru- 

 ments of locomotion in their stead*. 



[To be continued.] 



XLIV. — Notes on Propithecus bicolor and Rhinoceros lasiotls. 

 By P. L. SCLATEK, M.A., Ph.D., F.R.S. 



The Lemur described by Dr. Gray in the last Number of the 

 'Annals' [anteh^ p. 206), as Propithecus bicolor ^ has been al- 

 ready named Propithecus Edxcardsi by M. Alfred Grandidier 

 (Compt. Rend. Ixxii. p. 231, 27 Feb. 1871). M. Milne-Ed- 

 wards, who has requested me to make known this correction, 

 informs me that he has examined a marked skin of this animal 

 received from Mr. E. Gerrard, jun., and has no doubt of the 

 identity of the two species. 



As regards the two Asiatic two-horned rhinoceroses in 

 the Zoological Society's Gardens, when the first s^jecimen ar- 

 rived from Chittagong I referred it to Rhinoceros sumatrensis, 

 that being the only species of this section then known to science. 



* Muller's Archiv, 1851, p. 351. 



