2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



4. Callyspongia vaginalis ( ?) (Lamarck) 1814, p. 436. One small 



specimen collected July 21 at Clipperton Island (Galapagos). 

 This species is nearly cosmopolitan. The specimen in question 

 does not agree well with ordinary examples of vaginalis, but is 

 approached by occasional specimens. 



5. MERRIAMIUM ROOSEVELTI, n. sp. 



Fig. 1 



Holotypc. — The sponge (U.S.N.M. no. 22614) was scraped from 

 an old anchor chain at Elizabeth Bay, Albemarle Island, Galapagos, 

 July 26, 1938 (sta. 20-38). It covers some other object, perhaps a 

 barnacle, and is 1 or 2 mm. thick. 



Fig. 1. — Merriamium roosevelti. A, dermal tylote ; B, endosomal 

 acanthostyle ; C, arcuate isochelas. All X 500. 



Description. — Color nearly white, consistency soft. The entire or- 

 ganism is very fine-grained, with pores and oscules too small to be 

 made out. The most remarkable items involved concern the skeleton ; 

 three sorts of spicules are present. 



1. Ectosomal special spicules are tylotes 3 by 180 micra. 



2. Endosomal spicules are abundant acanthostyles, heads with tubercles 



rather than spines, size n by 120 to 15 by 170 micra. 



3. Microscleres are abundant arcuate isochelas with a semicircularly 



curved shaft and very small clads ; the chord diameter varies from 

 21 to 24 micra. 



Remarks. — A review of the genus Merriamium and a key to its 

 several species is here presented to indicate better the relation of the 

 new species to the members of the genus and also their relation to each 

 other. 



LIST OF PREVIOUSLY KNOWN SPECIES OF THE GENUS MERRIAMIUM 



a. Merriamium atlanticum was described as Ectyodoryx a. by Steph- 

 ens, 1916, p. 238, from Ireland. The ectosomal spicules are 



