REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 159 



Drulia batesii (Bowerbank, 1863) 



Plate 15, figures 10-12 



Spongilla batesii Bowerbank, 1863, p. 459. 



Drulia batesii Gray, 1867, p. 552. 



Parmula batesii Carter, 1881a, p. 99.— Potts, 1887, p. 256. — Weltner, 1895, 

 p. 114.— Cordero, 1923, p. 134; 1925, p. 113; 1928, p. 259.— Gee, 1931e, 

 p. 33; 1932c, p. 35.— De Laubenfels, 1936, p. 37.— Jewell, 1952, p. 450.— 

 Penney, 1960, p. 54. 



Material. — Slides of type (BM) and syntype (N. Gist Gee). 



Description. — Sponge forming subspherical to spherical growths 

 on submerged twigs; surface coarsely reticulate and hispid due to the 

 projection of thornlike spicule fibers through dermal membrane. 

 Skeleton consisting of strong radial and somewhat slimmer transverse 

 spicule fibers; both forming an open but very firm and compact 

 network of wide meshes. Consistency of live sponge hard but brittle. 



Megascleres stout and almost cylindrical, exceptionally broadly 

 fusiform, smooth amphioxea with abruptly pointed tips; the latter 

 occasionally rounded, resembling amphistrongyla ; all scleres dis- 

 tinctly of two lengths, length range of longer series 320-410 n, of 

 shorter 220-300 n; width range of longer series 27-30 n, of shorter 

 22-28 n. 



Microscleres extremely abundant in symplasm and particularly in 

 the vicinity of gemmules; they are thin and pointed amphioxea, almost 

 straight, covered with smaller spines at then* extremities, and with 

 larger erect spines in their central portion; length range 54-72 ju, 

 width range 3-4 fi. 



Gemmoscleres typically parmuliform, rotule with a pronounced 

 internal conical depression, and with more or less circular and re- 

 curved margin; diameter of rotule 26-28 ju. 



Gemmules enclosed in rigid capsules formed by the smaller class of 

 megascleres, scattered throughout the skeletal meshwork, spherical 

 and very large; diameter ranging 590-720 n; pneumatic layer well 

 developed and thick, distinctly granular; parmuliform gemmoscleres 

 embedded in two layers, one surrounding the inner gemmular mem- 

 brane, the other just below the outer gemmular membrane, with their 

 tips projecting through it; outer membrane well developed, distinctly 

 corrugated and containing, apart from the gemmoscleres mentioned, 

 a great number of reinforcing microscleres; foramen produced into a 

 moderately wide and short porus tube, bearing a peripheral collar, 

 with a group of slanting gemmoscleres surrounding it. 



Distribution. — Known only from South America. 



Color in life. — Not yet reliably recorded. 



