206 ANATOMY AND PHYSIOLOGY 



character of the skeleton fibre readily serves to distinguish 

 them. Fig. 379, Plate XXXVII, exhibits the irregularity 

 of the disposition of the keratose fibres from one of the 

 best Turkey sponges of commerce, X 50 linear, and Fig. 

 261, Plate XIII, a fibre from a similar description of sponge, 

 from a specimen preserved in spirit in the condition in 

 which it came from the sea, X 175 linear. 



The second genus is founded on the specimen described 

 by Sowerby in the ' British Miscellany,' p. 87, plate xlviii, 

 and named by him Spongia pulcheJIa. I fortunately have 

 this specimen, and on carefully examining it I find it to 

 possess all the characters of the genus Spongia, excepting 

 that the reticulations of the skeleton are very symmetrical, 

 and this is so important a structural difference that I have 

 thought it advisable to constitute it the type of a new genus 

 the characters of which are as follows : 



SPONGIONELLA, Bowerbank. 



SPONGIA, Sowerby and Johnston. 



Skeleton kerato-fibrous. Fibres solid, cylindrical, aspicu- 

 lous. Rete symmetrical ; primary fibres radiating 

 from the base to the apex. Secondary fibres disposed 

 at nearly right angles to the primary ones. 



Type, Spongionella pulcheUa, Bowerbank. 



Fig. 380, Plate XXXVII, represents a section at right 

 angles to the surface from the type specimen Spongia pul- 

 chella, Sowerby, showing the nearly regular rectangular 

 mode of disposition of the primary and secondary fibres of 

 the skeleton, X 50 linear. 



Suborder II. Solid, semispiculate, kerato-fibrous skele- 

 tons. 



The sponges of this suborder closely resemble in general 

 appearance those of the genus Spongia, but they differ very 



