Miscellaneous. 261 



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

 former of these names consequently remains undetermined. Lastly, 

 Gray's Petalastres arc true Luidicc. 



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

 lensis, Miill. & Tr., and the Goniaster africanus of Verrill from the 

 African coast, with L. Marccjravn, Steenstr., and G. americanus, 

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

 LincJcia GuUding'd 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 woi'k 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 300 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 very doubtful have been 

 described afresh from the original specimens ; and 50 new Stellerida 

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

 December 3, 1875, p. 1271. 



On an Amphipod (Urothoe marina), « Commensal o/ Echinocardiura 

 cordatum. By M. A, Giakd. 



The sandy shore that stretches between Wimereux and Amble- 

 teuse furnishes in abundance Eohinomrdium cordatum^ known to 

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

 has given us some details as to the mode of life of this Spatangus* ; 

 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 quill, one of which terminates at the central point of 

 the ambulacral star, and the other at the anal apertui-e. 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 nutrition, 

 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 through the madreporic plate into the general cavity and 

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

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

 stream of water, the existence of which is difiicult to exphdn, since 



* Quart. Journ. Micr. Sci. xi. p. 25. 



