REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 95 



components, as well as by the much more conspicuous armature of 

 spines on its megascleres. Both E. ramsayi and the E. jortis group 

 occur in neighboring regions of the Indo-West Pacific, therefore it is 

 possible to consider them the result of speciation trends in distant 

 populations of one species. Additional material from New Caledonia 

 seems to substantiate this assumption. Although it is most likely 

 that future studies, leading to the introduction of a trinomial nomen- 

 clature for spongiUids, will ultimately relegate all species of the 

 E. jortis gi'oup to mere subspecies of E. ramsayi, the paucity of material 

 and data available makes such a decision at the present impossible. 

 The separate specific status of E. jortis is therefore here retained, 

 and the "varieties" E. j. hebridensis and E. j. vorstmani relegated to 

 its synonymy. 



Ephydatia jluviatilis var. etorohuensis Sasaki, judging from its 

 description and illustrations, is tentatively considered synonymous, 

 although its gemmoscleres are slightly smaller and less crowded than 

 usually found in this complex. 



Ephydatia millsii (Potts, 1887) 



Plate 7, figures 1-3 



Meyenia millsii Potts, 1887, p. 225.— Kellicott, 1891, p. 103.— Kirsch, 1909, 

 p. 37.— Eshleman, 1950, p. 40.— Pennak, 1953, p. 91.— Penney, 1960, p. 51. 



Ephydatia millsii Weltner, 1895, p. 114.— Smith, 1921, p. 17.— Gee, 1931e, p. 43; 

 1932c, p. 30. 



Material. — Slides of a specimen from Florida (N. Gist Gee). 



Description. — Sponge, according to previous descriptions, forming 

 flat crusts of moderate thickness; surface slightly hispid but generally 

 even, oscula apparently inconspicuous. Skeleton forming an irregular 

 network of spicule fibers, loosely joined together by a small amount of 

 spongin. Consistency of live sponge recorded as soft, texture loose. 



Megascleres feebly curved to almost straight amphioxea, almost 

 cylindrical, armed with numerous small spines except at their tips; 

 in distal parts of the scleres these spines often inserted at an angle, 

 pointing to spicular tips length range 180-270 fi, width range 9-12 /x. 



Microscleres absent. 



Gemmoscleres birotulates of almost constant lengths and dis- 

 tinctly of one class; their shafts are concave, widening towards the 

 rotules, and invariably entirely smooth; their rotules are of equal 

 diameter and distinct flat shape, representing circular disks with 

 incipient crenulations or extremely small incisions at their margins, 

 outer surface often granulated; length of shaft 36-48 n, diameter of 

 rotules 23-28 /x- 



Gemmides moderately abundant, subspherical to spherical, ranging 

 in diameter 300-360 m; pneumatic layer regularly but somewhat 



