REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 121 



the complete absence of their terminal rotules^point to malformations 

 of the spicular components of the gemmular armatm^e due to un- 

 known factors. Whether these malformations are the result of hybrid- 

 ization or caused by adverse chemical properties of the environment 

 is a problem which can be solved only by future detailed studies of 

 additional material. Until then it appears advisable to retain the 

 separate specific status of ^. biceps so that possible taxonomic evidence 

 will not be obscured. 



Umhorotula, new genus 



Ephydaiia Weber, 1890, p. 33 (part). — Weltner, 1895, p. 114 (part). — Evans, 

 1901, p. 71.— Annandale, 1911, p. 54 (part); 1918a, p. 201 (part).— Gee 

 and Wu, 1925b, p. 393 (part).— Vorstman, 1927, p. 184 (part).— Gee, 1926c, 

 p. 110 (part); 1927a, p. 1 (part); 1927b, p. 61 (part); 1928, p. 225 (part); 

 1929d, p. 297 (part); 1930a, p. 84 (part); 1930b, p. 170 (part); 1931e, p. 34; 

 1932a, p. 449 (part) .— Arndt, 1932c, p. 564 (part) .— Suvatti, 1950, p. 3 

 (part) . 



Meyenia Penney, 1960, p. 46 (part). 



Type species. — By monotypy Ephydatia bogorensis Weber, 1890. 



Definition. — Megascleres long and slender amphioxea, usually 

 covered with a small number of minute and inconspicuous conical 

 spines, rarely entirely smooth. 



Microscleres absent. 



Gemmoscleres birotulates of equal length, with rather long shafts 

 covered with large conical spines, and at either end with conspic- 

 uously umbonate rotules of equal size and shape; margin of rotules 

 slightly recurved, bearing a large number of small and regular 

 indentations. 



Gem mules rather scarce, large and spherical; pneumatic coat well 

 developed, granular, consisting of minute and regular air spaces; 

 gemmoscleres embedded in this layer strictly radially, their basal 

 rotules almost touching each other; foramen distinctly tubular, tube 

 delicate and in length only slightly surpassing width of pneumatic 

 layer. 



Sponges forming delicate cushions of small size on aquatic plants; 

 coloration usually vivid green, owing to the presence of zoochlorellae. 

 Consistency soft and fragile. 



Apparently restricted to Southeast Asia. 



Discussion. — As a result of Pott's (1887) erection of Heteromeyenia, 

 a certainly meaningless genus formerly including all spongillid species 

 with heterogeneous birotulate gemmoscleres, the only species of 

 Umborotula was left by all previous authors in the genus Ephydatia 

 i=Meyenia) for the simple reason that its gemmoscleres are homo- 

 geneous. It is quite obvious that such an arrangement cannot be retained 

 in modern spongillid taxonomy, since E. bogorensis Weber differs 



