SILICIOUS AND HORNY SPONGES WILSON. 383 



The Albatross sponge is evidently close to Kieschnick's species, 

 which Hentschel has more recently (1912, p. 331, Cinachyra am- 

 boinensis) recorded from the Aru Islands. Hentschel calls the ecto- 

 somal spicules orthotriaenes, and says the rays vary in shape and 

 length. Kieschnick's type was ovoidal, blue gray, with an apical 

 osculum and small cloaca; root tuft at the lower end; poriferous 

 pits ; the ectosomal megascleres varying from regular " Vierstrahler " 

 (calthrops) to "modifications of an ordinary triaene" (his figures 

 are not decisive in this matter). The Albatross sponge differs too 

 much from this in habitus, and especially in the character of the 

 ectosomal triaenes, to be identified as the same species. 



Under the genus we may then record, to date: Paratetilla bacca 

 (Selenka), P. amboinensis (Kieschnick), P. cineriformis Dendy, 

 P. excentrica Row (1911, p. 306), a form in which the ectosomal 

 triaenes are very irregular, and the species here described. Dendy, 

 it should be added, who has recently (19215, pp. 21-25) studied a 

 number of specimens from the Indian Ocean, would follow Thiele's 

 practice and accept P. bacca as a comprehensive variable species to 

 include all that Thiele (see above) put into it and also his own 

 P. cineriformis and P. eccentrica Row. Within this species he re- 

 tains one of Kieschnick's names as a variety, var. violacea, and estab- 

 lishes a new variety, corrugata, in which the very numerous pori- 

 ferous pits (porocalices) tend to become confluent. 



The sponge from Amboina designated by Topsent, 1897, p. 437, 

 Tetilla merguiensis, since it has amphitriaenes, would appear to be 

 a distinct species referable to Am/phitethya Lendenfeld. This is cer- 

 tainly a more objective treatment than to interpret the amphitriaenes 

 as abnormalities. 



Likewise Paratetilla aruensis Hentschel, 1911 (p. 329), is referable 

 to Amphitethya, although Dendy has recently (19215, p. 21) ex- 

 pressed the opinion that it may be left in Paratetilla. Hentschel, it 

 should be added, would merge the two genera, while Dendy thinks 

 they may be kept separate. 



The remaining genera of the family are not represented among 

 the sponges studied. They are defined and discussed below. 



Genus CINACHYRA Sollas (1886). 



Cinachyra Sollas, 1886, p. 183; 18S8, p. 23.— Part, Lendenfeld, 1903, p. 

 26.— Part, Dendy, 1921&, p. 11. 



The ectosome is a fibrous cortex traversed by radial cortical oxeas. 

 Poriferous depressions with sphinctrate mouths are present. In 

 some species there are also simple oscula. 



Sollas, 1888, regarded some of the poriferous depressions as af- 

 ferent, others efferent. The facts as a whole confirm, I think, this 

 interpretation. Nevertheless Kirkpatrick has (1905) found simple 



