REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 103 



understanding of the range of criteria in Heterorotula may yet result in 

 the erection of a trinomial nomenclature, separating the various species 

 on a subspecific level. Until this will be possible, it is advisable not to 

 obscure possible taxonomic evidence and to retain the different 

 members of this genus, at least provisionally, as distinct species. 



Heterorotula kakahuensis (Traxler, 1896) 



Ephydatia kakahuensis Traxler, 1896a, p. 30. — Gee, 1931e, p. 41; 1931d, p. 46; 



1932c, p. 30.— Schroder, 1935, p. 101. 

 Meyenia kakahuensis Penney, 1960, p. 51. 



Material. — Shdes of syntype (LeidM) ; shdes of material from New 

 Zealand (N. Gist Gee). 



Description. — Sponge, according to Traxler (1896a) and Schroder 

 (1935), forming encrustations of various dimensions and of soft con- 

 sistency; other criteria still insufficiently known. 



Megascleres slender amphioxea, as a rule covered with a varying 

 number of inconspicuous spines except at their tips, only exceptionally 

 enthely smooth; length range 185-260 fi, width range 9-12 fi. 



Microscleres absent. 



Gemmoscleres not present in the material available for the present 

 study; those described by Traxler (1896a) and Schroder (1935; are 

 birotulates of comparatively smaU size differences, possessing smooth 

 shafts and nongranulated flat discs of slightly unequal size; length 

 range of gemmoscleres 30-42 n (Schroder), diameter of rotules ranging 

 17-22 M. 



Gemmules were not seen by the authors; they were described by 

 Schroder to be spherical, ranging in diameter 380-540 /x, and devoid 

 of an outer gemmular membrane; foramen apparently simple, sur- 

 rounded by an elevated collar. 



Distribution. — Known only from New Zealand. 



Color in life. — Not yet observed. 



Discussion, — No gemmules or even a single gemmosclere were con- 

 tained in the shdes examined during the present study or in the syntype 

 specimen from LeidM examined by the wTiter on an earher occasion. 

 The systematic position of this species must therefore remain un- 

 certain until additional material from New Zealand can be obtained. 

 From the accounts of previous authors it is very likely that E. 

 kakahuensis Traxler is a member of this genus, since most of its 

 known criteria clearly fit its definition. Instead of listing this species 

 as a dubious one, the authors consider it advisable to include it 

 provisionaUy in the genus Heterorotula until evidence as to the con- 

 trary can be demonstrated. 



