384 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



oscula, or oscular eminences, over the upper surface of G. barbata 

 Sollas. Kirkpatrick reviews the species and thinks probably the 

 records are deficient and the species all have simple oscula like C. 

 barbata. It is difficult to believe that this is universal (see Tetilla 

 crustata of this report), unless indeed, as I have suggested (under 

 Tetilla crustata, var. aperta), one and the same poriferous depres- 

 sion may in a different physiological state of the individual come to 

 appear as a simple cloaca or as the terminal part of a main efferent 

 canal. 



Some of the species enrolled by Lendenfeld, 1903, and Dendy, 

 19216, under Ginachyra fall under Tetilla according to the classifi- 

 cation followed in this report. Kirkpatrick (1905 p. 666) indeed 

 judges from the records that in only one of these species, G. barbata, 

 is there a fibrous cortex " with a dense palisade of oxeas." 



Since the Tierreich synopsis (Lendenfeld, 1903) Lendenfeld (1906, 

 1907), Hentschel (1911, 19i2), Kirkpatrick (1908), and Dendy 

 (19216) have recorded a number of new forms under Ginachyra. 

 They all fall under Tetilla (Ginachyrella) as used in this report. 

 Dendy, 19215, discusses the differential features of the species which 

 he groups under Ginachyra and gives a useful key. 



Genus AMPHITETHYA Lendenfeld (1906). 



Amphitethya Lendenfeld, 1906, p. 126. 



With microscleres, without vestibular poriferous depressions, with 

 amphiclads (amphi- triaenes, -diaenes, -monaenes). 



Lendenfeld, 1906, under this head combines with a new species, 

 A. microsigma, some old ones previously described under Tetilla. 



Among these is Tetilla (Tethya) stipitata (Carter), in which the 

 characteristic generic spicules, amphitriaenes, " very variable in 

 form and size " and sometimes " reduced to simple triaenes," occur in 

 the basal (stem) part of the sponge (Sollas, 1888), and which there- 

 fore fits well in the genus. In Lendenf eld's species, A. microsigma, 

 amphitriaenes, connected by transitional forms with plagiotriaenes, 

 occur and also only in the stalk. 



Lendenfeld also lists here somewhat provisionally Tetilla (Tethya) 

 bacca (Selenka). The synonymy of T. bacca is confused, as Dendy 

 has said (1905). Lendenfeld, 1903, following Lindgren and Thiele, 

 combined under this head several sponges, among them the sponge 

 from Amboina described by Topsent (1897) as Tetilla merguiensis. 

 This sponge has amphitriaenes and is accordingly referable to 

 Amphitethya. In the other sponges combined by Lendenfeld under 

 T. bacca, amphitriaenes are not recorded; these sponges are as- 

 signable to Paratetilla.. It thus comes about that T. bacca is men- 

 tioned by Dendy, 1905, under Paratetilla. and by Lendenfeld under 

 Amphitethya. 



