Miscellaneous. 261 



young O. carinifera. The species designated by Vcrrill under the 

 former of these names consequently remains undetermined. Lastly, 

 Gray's Petalastres arc true Luldice. 



I may add that I cannot doubt the identity of the Luidia senegn- 

 leusis, Miill. & Tr., and the Goniaster africanus of Yerrill from the 

 African coast, with L. Marcgravii, Steeustr., and G. americanus, 

 Yerrill, of the American shore. Asterina stellifera, Mobius, and 

 Linckia GuihUngii are likewise common to both shores. 



To sum up : with 200 species, represented by about 1200 speci- 

 mens, the collection of the Museum possesses nearly half the known 

 species of true starfish, the number of which, according to the lists that 

 I have prepared, may be estimated at 420. In the work of revision 

 that I have just terminated, 1 did not think I ought to confine my- 

 self to the species of our Museum. I have included all those that I 

 have had an opportunity of examining, making a total of o'-'O species, 

 including close upon 2500 specimens, as to which I have brought 

 together precise information, with regard to both their synonymy 

 and their geographical distribution, the origin of each specimen 

 having been carefully ascertained. These species are divided into 

 46 genera, many of which had to be created or remodelled. A 

 great number of old species which had been verj- doubtful have been 

 described afresh from the original specimens ; and 50 new Stellerida 

 have been added to the list of known species. — Comptes lienchis, 

 December 3, 1875, p. 1271. 



On an Amphipod (Urothoe marina), a Commensal of Echinocardium 

 cordatum. By M. A. Giakd. 



The sandy shore that stretches between Wimereux and Amble- 

 teusc furnishes in abundance Echinocardium cordatum, known to 

 the fishermen under the name of ceuf de Grisard. Dr. llobertson 

 has given us some details as to the mode of Ute of this Spatanjus* ; 

 but his statements are incomplete and even sometimes incorrect. 

 The urchin lives in the sand at a depth of from 15 to 20 centi- 

 metres ; it communicates with the surface by two canals of the 

 thickness of a (juill, one of which terminates at the central point of 

 the ambulacral star, and the other at the anal aperture. This 

 second canal has not been noticed by Dr. llobertson, who thinks 

 that the sand introduced into the digestive cavity of the animal 

 must be disgorged by the mouth after having served for nutritiun, 

 thanks to the organic materials that it contains. The aperture of 

 the anal tube is perfectly circular ; that of the apical tube is irregu- 

 larly three-lobed. The water penetrates by this latter tube, which 

 contains the long contractile filaments ("locomotive feet," " ringed, 

 worm-like suckers "), the movement of which conveys the alimen- 

 tary particles to the mouth by the anterior furrow. A portion of the 

 water enters througli i\\Q maclrwporic plate into the general cavity and 

 aquiferous system. The anal canal ^serves for the escape of the sand 

 that has traversed tlie digestive tube. This canal is traversed by a 

 stream of water, the existence of wliich is diiKcult to exi)lain, since 



* (^iiart. .loum. Micr. 8ci. xi. p. Jo. 



