Miscellaneous. '367 



Thus I have several times found at Saint-Vaast a passage form m 

 which the posterior half of the body was reduced by burying itself 

 in the anterior part, which was margined at the base by the ciliary 

 circlet. This fact quite naturally leads us to regard the Mitraria 

 as produced by the same process a little more strongly marked ; the 

 second period of development, in which Metschnikoff has seen the 

 segmented body coming to form a more or less considerable hernia 

 beyond the anterior parts, which at first covered it completely, 

 would then be nothing but the inverse of the first, and a simple 

 return to the normal form. — Comptes Mendus, July 30, 1877, 

 p. 297. 



On a new Genus of the Family Tritoniidae. By M. A. Vatssiere. 



Among the numerous Gasteropod MoUusca collected in the Gulf 

 of Marseilles, I have observed a curious Tritoniid which I do not 

 find described anywhere, and which certainly merits special men- 

 tion. This animal was captured on the 26th April last, between 

 Carry and Cape Mejeau, at a depth of 50 metres, on a muddy bottom, 

 nearly at the limit of the coralligenous bottom. 



It so much resembled some Dendronoti which I had received at the 

 same time in its external aspect, in its size (7-8 centims.), and in 

 its coloration, that I at first confounded it with them. When I 

 perceived my error the animal was too much decomposed to allow a 

 sketch of it to be made ; nor could I completely examine its external 

 characters : the anterior region of the integuments, however, was 

 still in a pretty good state. But a dissection was sufficient to bring 

 to light the important anatomical peculiarities which determine me 

 to establish a new generic group for this moUusk. 



I may be pennitted to dedicate this new genus to my teacher, 

 Prof. Marion, as a very feeble testimony of the gratitude I owe him 

 for the constant kindness with which he directs me in my natural- 

 history studies. 



Genus Mamonia. 



Corpus elongatum, lateribus compressis, altius quam latius, paUio 

 nullo. Caput subinferius, obtectum velo parvulo, ramoso ; maxiUis 

 cornels. Stomachus cultriformibus dentibus armatus. Tentacula 

 duo dorsalia ramusculis tenuibus condensis superne cincta. Branchias 

 ramosae, linea unica utrinque dorsi insertae. Orificia generationis et 

 ani ad latus dextrum sita. 



The general coloration of this mollusk was ochre-yellow, with 

 numerous vinous spots. Its dendritic branchiae were shorter and 

 less divided than those of Dendronotus. 



The tentacles, instead of presenting, as in the latter, towards their 

 upper part a certain number of ridges and lamellae, showed a mass 

 of ramifications, very like much-attenuated branchiae, pressed close 

 together, and only allowing to project the terminal, much lessened 



