Miscellaneous. 317 



immediately below the crown of anal papillae, there is also a calca- 

 reous ring composed of ten pieces, of very regular form ; and the 

 five radiate muscles of the intestine are attached to the five radial 

 pieces. The calcareous ring of the pharynx is placed a little deeper 

 in the peduncle than that of the intestine ; therefore a section of the 

 peduncle at the level of the root of the buccal tentacles shows 

 plainly the five radial muscles of the intestine, but not those of the 

 pharynx. The small dimensions of the object have not, unfortu- 

 nately, allowed it to be ascertained how the aquiferous vessels of the 

 rays behave in the neighbourhood of the calcareous rings. The 

 existence of a double calcareous ring and the division of the rays 

 itito five intestinal and five pharyngeal rays might lead us to suppose 

 that there exist two circular vessels. If, however, we admit, de- 

 spite this arrangement, a single nervous ring and a single circular 

 aquiferous vessel, it is still no less impossible to refer this singular 

 animal to the typical form of the Holothuriae, notwithstanding the 

 incontestable affinities that have been indicated in the internal 

 organs. We might, it is true, suppose the Rhopalodince to have 

 resulted from a Psolus or Colochirus whose buccal and anal cones 

 had been much elongated and soldered to one another ; but although 

 that transformation might produce a form smalogous to Rhopahdinay 

 the rays could not be arranged as in these animals. The two dorsal 

 rays should, on the contrary, disappear entirely, and we ought to 

 find on the peduncle two groups of three rays becoming continued 

 one into the other at the extremity of the abdomen. 



In all living Echinoderms the anus is placed either opposite to the 

 mouth in the centre of the radiate arrangement or in an inter- 

 radium. In some fossil Crinoids alone (the Crinoidea tessellatd) 

 there exist more than five rays placed round a single central aper- 

 ture. These are in reality the only Echinoderms in which we could 

 suppose an arrangement of the pharynx and intestine in relation to 

 the rays like that which M. Semper has described in Rhopalodina. 

 Yet these latter could not be united with the Crinoids, because of 

 the totally different structure of their ambulacra, leaving out of 

 consideration that their internal organs approximate them much 

 more to the Holothuriae. 



The author does not see any other way of getting out of the diffi- 

 culty than to create for these singular animals a new class, under 

 the name of Echi7iodermes diplostomes. He promises us a detailed 

 description of the genus Rhopalodina in a supplement to his great 

 work on the Holothuriae. — Verhandl, phys.-med. GeseTlsch. in 

 Wurzhurg, June 6, 1868 : Bill. Univ. August 15, 1868, Bull. Sd. 

 pp. 326-328. 



Coccoliths and Coccospheres. By G. C. Wallich. 



September 7, 1868. 



In a lecture " On a Piece of Chalk," delivered by Prof. Huxley 

 to working men during the recent meeting of the British Association, 

 and published with the author's initials in the September number of 



Ann. & Mag. N. Hist. Ser. 4. Vol. ii. 22 



