SPONGES.-HALLMANN. 20X 



Echinochalina, and at the same time has fixed upon T. typica 

 as the type of Thalassodendron. Unfortunately no specimens 

 identifiable with either of these species occur in the present 

 collection of the Australian Museum, and since the description 

 of T. typica is insuflficient, we are left in doubt as to the precise 

 connotation of the name Thalassodendron. Whiteiegge^ has 

 indeed published a short account of a sponge regarded by him 

 as the type-specimen of T. typica, but it is so little in agree- 

 ment with the original description that hesitation might well 

 have been felt in accepting its implication as a final verdict. 

 An examination of this specimen has shown — what is indeed 

 immediately obvious even from external comparison — that it 

 is an example of Echinodictyuni [Kalykenteron) elegans, Len- 

 denfeld,2 a sponge with which Whitelegge was apparently 

 not well acquainted. One can therefore only conclude that the 

 specimen investigated by Whitelegge was mislabelled, as was 

 also the specimen which he at first mistook^ for TJtalas- 

 sodendron viminalis. So far as one can judge from Lenden- 

 feld's description of 7'. typica, Thalassodendron mav for the 

 present be looked upon as a synonym of Wilsonella {q.v.). 



T. viminalis is an Ophlitaspongia.^ With regard to the 

 remaining species I find, in disagreement with Whitelegge 

 who regarded them as individual variations of a single species, 

 that T. hrevispina is a variety of Rhaphidophlus typicus, 

 Carter; that T. rubens var. lamella and T. paucispina are 

 identical {Rhaphidophlus paucispinus) ; and that T. rubens 

 var. dura is a Clathria (C. rubeyis). Owing to the unsatis- 

 factory nature of the descriptions of these species, a further 

 and more extended account of them has been included in the 

 present paper. 



Genus Pleciispa, Lendenjeld. 



1888. Plectispa, Lendenfeld, Descr. Cat. Sponges Austr, 

 Mus., 1888, p. 225. 



The description which Whitelegge has gi\en of Lendenfeld 's 

 three species of Plectispa, viz., P. elegans, P. arbor ea, and 

 P. macropora are so little in agreement with those of Lenden- 

 feld as to render inevitable the conclusion that the specimens 

 invesigated were mislabelled. How completely at \ariance 

 are the two accounts of these species, will be evident from a 

 comparison of the following summaries of them. 



1 Whitelegge— Eec. Austr. Mus., iv.. 2. 1901, p. 86 



2 Lendenfeld— Cat. Si)onges Austr. Mus.. 1888, p. 216. This species, which 

 is probably identical with E. hilnmellatum, Lamk.. is described herein, 

 p. 171. 



3 Whitelegge— Eec. Austr. Mus., iv., 2. 1901, p. 87; and 5. 1902. p. 214. 



4 O- snbhispida. Carter, var. vnniiKilin, Lendf. iti.v.) 



