114 U.S. NATIONAL MUSEUM BULLETIN 272 



subspherical air spaces; shorter gemmoscleres entirely contained in 

 this layer, longer set protruding through outer gemmular membrane; 

 foramen distinctly tubular, porus tube slender and very long, ranging 

 from 0.5 to 0.9 diameter of gemmule, slightly enlarged at its distal 

 margin, and bearing five to six long cylindrical cirrous appendages. 



Distribution. — Apparently restricted to the eastern half of the 

 North American Continent, ranging from Louisiana to Canada ; record 

 from Italy (Garbini, 1897) based on the presence of one spicule, prob- 

 ably a result of wrong identification. 



Color in life. — Recorded as ranging from brown to green. 



Discussion. — This species can be distinguished from other congeners 

 at a glance by the unusually long porus tube, as well as by the char- 

 acteristics of the gemmoscleres. Furthermore, its comparatively mas- 

 sive mode of growth, an unusual feature of the genus Heteromeyenia as 

 here restricted, should represent a most valuable factor in its identifica- 

 tion in the field. 



Although Mills (1880) was first to give a detailed description of this 

 spongillid, he failed to give it a name; consequently Potts (1881a) 

 redescribed it under the name of Carterella tubisperma. In spite of the 

 fact that Mills was thus considered the original author of this specific 

 name, H. tubisperma must be correctly associated with Potts and not 

 with Mills. 



Genus Anheteromeyenia Schroder, 1927 



Heteromeyenia (Anheteromeyenia) Schroder, 1927b, p. 108. — Gee, 1931e, p. 32. 

 Anheteromeyenia de Laubenfels, 1936, p. 36. 



Heteromeyenia Potts, 1881a, p. 150 (part) ; 1887, p. 236 (part.)— Eshleman, 1950, 

 p. 41 (part).— Jewell, 1952, p. 455 (part) .—Penney, 1960, p. 40 (part). 



Type species. — By present selection Spongilla argyrosperma Potts, 

 1880. 



Definition. — Megascleres usually stout amphioxea, only oc- 

 casionally amphistrongyla, as a rule conspicuously to coarsely spined. 



Microscleres absent. 



Gemmoscleres birotulates of two distinct series, each differing from 

 the other in length, as well as often also in shape; the shafts of both 

 series usually bearing a number of strong conical spines; rotules of the 

 longer class relatively smaU, consisting of a number of strongly 

 recurved hooks, or irregularly shaped; rotules of shorter class flat 

 to sHghtly dome-shaped, typically with a larger number of marginal 

 teeth. 



Gemmules moderately large to large, subspherical to spherical, 

 scattered throughout skeletal mesh work; pneumatic layer well 

 developed and typically thick, granular, consisting of minute sub- 

 spherical air spaces; gemmoscleres embedded in this layer strictly 



