Sollas — On Tetractinellid Sponges. 181 



collenchyme, with acerate spicules strewn through it in various 

 directions, but not at right angles to the surface ; the mesoderm is 

 a granular collenchyme ; the canal system eurypylous, or aphodal. 



Chrotella simplex, sp. n. Sponge somewhat spherical ; surface 

 pilose ; oscules, one or more, minute. Spicules — (1) fusiform 

 acerate, 3'0 by 0*0237 mm. ; (2) trind fork; shaft, with a filiform 

 end, 3-4 by 0*02 mm. ; rays, 0-158 by 0-016 mm.; (3) anchor; 

 shaft, with a filiform end; axial fibre produced distally beyond 

 the origin of the rays ; shaft, 5-35 by 0*016 mm. ; (4) sigmella 

 and arculus, 0118 mm. long. 



Habitat— Lat. 16° 50' N. ; 25° 8' W. 260 fms. 



Chrotella macellata, sp. n. — Sponge spherical, depressed, with a fiat 

 base ; oscules multiple, each leading into a large cloacal chamber ; 

 surface, hispid ; flagellated chambers small. Spicules — (1) fusiform 

 acerate, 5 *7 by 0-055 mm. ; trifid forks, with short prongs, highly 

 porrectate, 0-08 by 0-02 mm. ; shaft, fusiform, 7*95 by 0*0276 mm. ; 

 (3) trifid fork, with longer rays, less porrectate, 0*23 by 0'02 mm. ; 

 shaft, 2 - 5 by 0*24 mm. ; (5) two-pronged (dicellate), and one- 

 pronged (macellate) forks, derived from No. 4 by reduction in the 

 number of the rays ; shaft, 3-49 by 0*0316 mm. ; prongs of dicel- 

 late form, 0-44 by 0-0316 mm. ; of macellate, 0*58 by 0*0316 mm. ; 



(6) anchors, shaft, 6*5 by 0*016 mm. ; rays, 0*06 by 0*014 mm. ; 



(7) arculi and sigmellse from 0*012 to 0'016 mm. long ; (8) a sig- 

 mella with two turns (= a spirula), characterizes the cortex, 0*03 

 to 0*04 mm. long. 



Habitat.— Lat. 11° 37' N. ; long. 123° 31' E. 18 fms. 



Genus 3. Craniella, O. Schmidt. — The cortex is differentiated 

 into an inner fibrous, and outer collenchymatous layer ; the latter 

 excavated by intercortical cavities ; the former traversed at right 

 angles by cortical acerates ; the mesoderm of the choanosome is 

 a sarcenchyme ; the canal system is aphodal. 



Craniella bowerbankii, sp .n. — The spicules include — (1 fusiform 

 acerates of the body, 3*26 by 0*047 mm., and of the cortex 1*4 by 

 0*04 mm. ; (2) forks, with a shaft, 5*12 by 0*024 mm. ; rays, 0*12 

 mm. long. ; spread, 0*06 to 0*07 mm. ; (3) anchor, 5*8 by about 

 0*02 mm. The axial fibre of the shaft is continued into the head 

 past the origin of the arms. Arculi and^sigmellse absent. 



