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.