DENDY NON-CALCAREOUS SPONGES 105 



the more distally placed oxea and the cladomes of the more distally placed trisenes 

 and monsenes projecting slightly beyond the surface. The spicule-bundles are 

 crossed at various angles by loosely scattered oxea. 



There is no cortex and (in unstained preparations) no visible distinction 

 between ectosome and choanosome. 



Spicules. (1) Oxea ; straight, slender, fusiform ; gradually and finely pointed 

 at each end ; measuring about 0-85 by 0-012 mm. 



(2) Protriaenes (sometimes disenes ?) ; with equal or unequal, slender, straight, 

 sharp-pointed cladi, and very long, slender shaft tapering off into a fine hair. 

 Shaft measured up to 1-1 mm. in length with a thickness of 0-004 mm. (near the 

 cladal end), and cladi about 0-033 by 0-002 mm. Both shaft and cladi are 

 sometimes of hair-like fineness. 



(3) Anamonsenes (Fig. 2fo) ; shaft measured up to 2-5 mm. in length (and then 

 probably broken off) ; of hair-like fineness throughout the greater part of its 

 length, attaining a thickness of 0-008 mm. immediately below the cladome ; 

 the single cladus sharply recurved, gradually and sharply pointed, measuring 

 about 0-025 by 0-008 mm. (at the base) in a well -developed example. 



(4) Slender, spirally twisted (contort) sigmata (Fig. 2c), of the usual Tetilla 

 type ; measuring about 0-009 mm. in a straight between extreme points. Very 

 numerous throughout the sponge. 



The most characteristic spicules of this species are undoubtedly the ana- 

 monsenes, and it appears to me a very noteworthy fact that, although these 

 occur in immense numbers, I have not met with a single anatrieene or anadisene. 

 The only other known species in which the anatrisenes appear to be represented 

 exclusively by anamonsenes is, so far as I am aware, Tetilla pedifera Sollas 

 [1888]. 



In Tetilla pedifera, however, there are, according to Sollas, no sigmata, nor 

 any other form of microsclere, an unusual feature which serves at once to distin- 

 guish it from T. pilula. On account of this character Lendenfeld [1903] has 

 included T. pedifera in his genus Tethyopsilla, but it is evidently very closely 

 related to T. pilula, and it may well be doubted whether Tethyopsilla is a 

 monophyletic genus. 



In Tetilla coronida Sollas [1888] anamonsenes occur together with anatrisenes. 



In Cinachyra hamata Lendenfeld [1906] anamonocnes sometimes occur alone 

 and sometimes associated with a few anatrisenes. 



Register Numbers and Localities. IV. 9 b, dredged off S.W. coast of Beyt 

 Island ; XXXV. 8 a, b, dredged off Dwarka, January '06. 



12. Tetilla barodensis n. sp. (Plate I., Figs. 3-3d). 



The single specimen in the collection is approximately spherical and about 



