Sollas — On Tetractinellid Sponges. 187 



(possibly not proper to the sponge), rays from 0-28 to 0-64 mm. 

 long; (5) acerella, 0-011 mm. long; (6) spini-spirula, 0-016 to 

 0-02 mm. ; (7) cylindrical spicules, with rounded ends (sausage- 

 shaped), 0-357 by 0*028 mm. ; these are confined to the cloaca. 

 Habitat. — St. Jago, Porta Praya. 



G-enus 4. Characella, g. n. — Similar to Normania, but dis- 

 tinguished by the absence of forks in the choanosome; and by 

 possessing only one form of flesh-spicule, which is an amphiaster 

 form of spini-spirule. 



Characella aspera, sp. n. — Sponge irregular in form ; growing 

 into irregular ridges, lobes, and folds ; oscules numerous ; pores 

 generally dispersed or collected within circular depressed areas. 

 Spicules— (1) acerate, 1-476 by 0-073 mm. ; (2) forks, shaft from 

 0-2 to 0-4 by 0-04 to 0-074 mm. ; arms, when simple 0-2 to 0-64 mm. 

 long; when bifurcate, primary rays, 0-143; secondary, 0-27 mm. 

 long; (3) acerella, 0-4 by 0-008 mm.; (4) amphiaster, 0-0276 to 

 0-0434 mm. long ; (5) globules 0-05 mm. in diameter. 



Habitat. — Station 122 ; lat. 2° 5' S. ; long. 34° 50' W. 350 fms. 



Family.— STELLETTIDiE. 



The genera of the family Stellettidse may be arranged in 

 sub-families, as follows : — 



A. Stellettidse with but one form of stellate. 



1. Sub-family. HOMASTERINA. 



Ectosome not a cortex — Myriastra. 

 Ectosome a cortex. — Pilochrota. Asterella. 



B. Stellettidee with more than one form of stellate (Heteras- 



terina). 

 (a) Both forms are stellates. 



2. Sub-family. STELLETTINA. 



Stellates are the only flesh spicules. 

 Without a cortex — Anthrastra. 

 With a cortex — Stelletta. 

 Trichite sheaves are also present — Dragmastra. 



