96 U.S. NATIONAL MUSEUM BULLETIN 2 72 



feebly developed, consisting of moderately large irregular air spaces; 

 gemmoscleres closely crowded together in this coat in a single layer; 

 foramen slightly elevated but simple. 



Distribution. — Known only from Florida, U.S.A. 



Color in life. — Apparently not yet recorded. 



Discussion. — This species is a sUghtly aberrant member of the 

 genus Ephydatia and can be easily separated from all its congeners 

 by the typical shape and serrations of its gemmosclere rotules. In 

 view of the regrettable fact that E. millsii must still be considered 

 as rather insufficiently known, detailed intrageneric comparisons 

 cannot be contemplated, and additional material and data are 

 extremely desirable. 



Heterorotula^ new genus 



Ephydatia Gray, 1867, p. 550 (part) .— Weltner, 1895, p. 122 (part); 1910, p. 



138.— Traxler, 1896b, p. 97.— Gee, 1931d, p. 25 (part); 1931e, p. 37 (part); 



1932c, p. 28 (part).— Schroder, 1935, p. 100. 

 Meyenia Carter, 1881a, p. 93 (part). — Haswell, 1882, p. 208 (part). — Penney, 



1960, p. 47 (part). 

 Tuhella Lendenfeld, 1887, p. 91.— Weltner, 1895, pp. 128 (part), 142 (not Tubella 



Carter 1881). 



Type species. — By present selection Spongilla capewelli Bowerbank, 

 1863. 



Definition. — Megascleres slender to stout amphioxea, occasionally 

 entirely smooth, but as a rule covered with a varying number of 

 minute scattered spines, except at their tips. 



Microscleres absent. 



Gemmoscleres birotulates of conspicuously unequal length, with 

 rather slender, usually granulated shafts, and terminally with com- 

 paratively wide and flat rotules of moderately to greatly varying 

 diameter, the inner invariably larger than the outer. 



Gemmules large and spherical, scattered throvighout skeletal 

 network in large and bulbous specimens, confined to the base in 

 encrusting forms; pneumatic layer very thick, granular, consisting 

 of minute spherical air spaces; gemmoscleres embedded in this layer 

 strictly radially, their inner larger rotules often interlocked with 

 each other to form a close covering of the inner gemmular membrane; 

 outer gemmular membrane corrugated by covering gemmoscleres of 

 varying length; foramen always simple, but sUghtly elevated. 



Young sponges often forming shallow encrustations of varying 

 size; mature sponges of massive or bulbous appearance, wdth uneven 

 surface or producing rounded lobes separated by deep clefts. Colora- 

 tion never green, sponges usually dark yellow to Ught tan. Consistency 

 varying from soft and fragile to rather hard but brittle. 



