ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 815 



latter ruethod, aud the definite statements of the German investigator 

 as to the madreporic plate being in connection with the water-vascular 

 system alone, have never been contradicted. The author allows that 

 be has never thought of looking for the connection between the 

 vascular apparatus and the ambulacral canals that has been recently- 

 stated to exist, by Perrier, but he more than doubts its existence. 



Ambulacra of Echinoderms.* — In a short critical note by M. E. 

 Perrier on the results arrived at by Niemiec from the study of the 

 ambulacra of the Echinoidea, he contends that these results are not 

 in contradiction to his own, and that the general statement to the 

 effect that it is possible to distinguish the regular from the irregular 

 urchins by the form of the calcareous parts of the ambulacra remains 

 true. 



Anatomy of Dorocidaris.t — M. Prouho finds that in Dorocidarts 

 both the intestinal siphon and collateral vessel, which are present in 

 Echinus, are wanting. The former, however, he considers may be 

 represented in a rudimentary state, by a kind of groove resulting from 

 a junction of the walls of the intestine along its first flexure, as this 

 canal occupies exactly the place of the intestinal siphon, and is not 

 met with in Echinoderms possessing the latter organ. 



" Tag " of Coelopleurus Maillardi.J— Prof. P. M. Duncan describes 

 the " tag" of Coelopleurus Maillardi Mich. The tissue on the " tag " 

 was separated and mounted. The base of the structure is a reticulate, 

 perforate, and more or less broadly spiculate calcareous layer or 

 layers, and the nucleated soft structures environ the hard parts. The 

 surface consists of connective tissue, minute nucleated cells showing 

 evidences of cilia, and extremely fine nerve-filaments. In three 

 places this common ectodermal structure became thick and rose into 

 three small bodies, each of which has a broad base and a surface of 

 digitiform and sometimes ragged processes. The surface of each of 

 the bodies is highly nucleated, but no trace exists of a central canal, 

 aud, indeed, the appearance given is that of solidity. There does not 

 appear to be any connection between the bodies on the tag and the 

 water-system of the ambulacra, and probably they act as respiratory 

 organs by increasing the surface of the common derm. 



New Species of Metacrinus.§ — Dr. P. H. Carpenter describes 

 three new species of Metacrinus. M. rotundus n. sp. is distinguished 

 by well-defined characters from the various types of Metacrinua 

 dredged by the ' Challenger,' and like M. Moseleiji it occupies an inter- 

 mediate position between the two groups into which most species of 

 the genus naturally fall — those with four radials of which the second 

 is a syzygy, and those with six radials of which both the second and 

 fourth are syzygies. M. sujjerhus n. sp. is the largest recent Pen- 

 tacrinite yet seen. M. Stewarii n. sp. is described from a stem- 

 fragment, which, however has well-defined characters. 



* Kecueil 5Sool. Suiese, ii. (1885) pp. 357-61. 



t Comptes Rondus, c. (1885) pp. 121-0. 



1 Ann. and Ma{<. Nat. Hist., xvi. (1885) pp. 88-0. 



§ TrauB. Linn. Soc. Loud. (Zool.), ii. (1885) pp. 435-14 (3 pla.)- 



