234 PROCEEDINGS OF THE ACADEMY OF [1887. 



nous coat and the other forming pait of the surface of the crust." 

 Carter. 



Loc. Bombay. 



Meyenia plumosa, var. palmeri, Potts. Proc. U. S. Natl. Museum, 1885, p. 

 587. (PL X, fig. Ti.) 



Sponge (as seen in a dry state) dark brown, massive, attached to and 

 surrounding the dependent branches of small trees whose stems are 

 flooded by the spring freshets. Texture very loose and when dry so 

 brittle that the dermal surface cannot be satisfactorily examined. 

 (The impression conveyed by the interior appearance of this sponge 

 is that it is made up of an infinite number of radiating, confluent 

 branches.) 



GemmuljB large, numerous throughout the deeper portions of the 

 sponge ; subspherical or ovoid, surrounded by long birotulates im-' 

 bedded in a granular crust. 



Skeleton spicules straight or slightly curved, mainly cylindrical 

 but gradually sharp-pointed, sparsely microspined. (PI. X. fig, vi, a.) 



Dermal sj)icules irregularly stellate as in the typical species, but, 

 in the specimens examined, much fewer in number. They vary 

 from simple acerates with one or more long divergent branches to 

 beautiful radiate-spherical bodies whose rays are nearly equal, spined, 

 and capitate by reason of recurved spines at their extremities. 

 (ibid, e, e, e, f.) Another foi'm of spicule, probably also dermal, 

 of which several are seen upon nearly every slide prepared for mi- 

 croscopic examination, is very difficult of description. It may be 

 said to be composed of an irregular series of smooth, curved rays 

 arising from a nearly common centre, and is somewhat suggestive 

 of a hedgehog or Scotch terrier, (ibid, g. g.) 



Birotulate spicules j^ertaining to the gemmulte, in length about 

 three times the diameter of the supported rotules ; shafts cylindrical, 

 plentifully spined ; spines long, conical. Outer surface of rotules 

 convex, margins lacinulate ; ends of incomplete rays obtuse, re- 

 curved, (ibid, b, c, d.) 



Sponge masses subspherical, reaching five or six inches in diam- 

 eter. 



This sponge, collected by Dr. Edward Palmer along the banks 

 of the Colorado River, near Lerdo, Sonora, in Northwestern Mex- 

 ico, about 59 miles S.S.W. from Fort Yuma, California, is a valuable 

 addition to the sjDonge fauna of this continent and interesting from 

 the fact that the typical species, M. plumosa of Carter, has hereto- 



