BY E. F. KALLMANN. 399 



Dendy, no spongin cementing them together is detectible. 

 Furthermore, in the typical species of Rhahderemia, including 

 R. indica, the spiculation includes very small scattered styli, — 

 designated microstyli by Topsent,— which, as they sometimes 

 show traces of a vestigial spination, are probably homologous with 

 the acanthostyli of "ectyonine" Myxillinse. The only two species 

 of the genus without microstyli are R. vntexta and R. prolifera. 

 The former of these is imperfectly known, but it appears to be 

 an encrusting species with a skeleton composed of rhabdostyli 

 distributed singly; in the latter, which is also encrusting, the 

 main skeleton consists of rhabdostyli standing separately with 

 their heads based on the substratum, and special dermal mega- 

 scleres are present in the form of slender tylostyli. The follow- 

 ing is a list of the species of Rhahderemia, with the spiculation 

 of each, and with references to their descriptions :— ^ 



R. toxigera Topsent (7). Smooth rhabdostyli, microstyli, sig- 

 mata, and toxa. 



R. gueritei Topsent (6). Smooth rhabdostyli, microstyli, sig- 

 mata, and ''thraustoxes." 



R. pusillti Carter f 2a); Topsent (9). Smooth rhabdostyli, micro- 

 styli, and sigmata. 



R. indica Dendy (3). Smooth rhabdostyli, microstyli, and 

 sigmata. 



R. spinosa Topsent (8). Spined rhabdostyli, microstyli, and 

 sigmata 



R. j^rolifera Annandale(l). Smooth rhabdostyli, dermal tylo- 

 styli, and sigmata. 



A*, inlexta Carter (2b). Spined rhabdostyli, and sigmata. 



Rhabdosigma MAMiMiLLATA Whiteleggc. 



CIO 



(Plate xxi., figs.l, 2: and Text-fig.2). 

 1907. Sigjnaxinella mammillata Whitelegge, Mem. Austr. Mus., 



iv., Part 10, p. 5 12. 

 1916. Rhabdosigma iiiwinniillata Kallmann, Proc Linn. Soc. N. S. 

 Wales, xli., Part 3, p.520. 

 External features. — The type-specimen (which is the only 

 example of the species so far obtained) may be described as pos- 

 sessing the form of a broad and low, moderately thick, erect 



