338 WILSOX. [Vol. IX. 



the order of formation of the canals. In some individuals the 

 first cavities formed are narrow rounded canals, ca>i., PL XXII, 

 Fig. ?>d>, covered in only by the dermal membrane, and which 

 from the surface look like oscula. Occasionally a stage is 

 found where but one of these canals exists, and that in the 

 centre of the body, Fig. 90. Such a stage is interesting, be- 

 cause of its essential resemblance to the young Reniera (Mar- 

 shall), or Chalinula (Keller), etc., in which sponges the first 

 canal to form is regularly a main central cavity which is 

 ordinarily homologised with the central cavity of calcareous 

 sponges and regarded as the gastrula cavity. 



Pores and oscula were developed in only a few of the sponges 

 I reared, and were themselves few in number. They made 

 their appearance without order, scattered about as in Esperella, 

 and in other respects too their formation agreed with that of 

 the same structures in the latter sponge. 



III. Adult Structure and Egg Development of 

 Tedanione Foetida, n. g. 



I. Adult. 



It is necessary to create a new genus for this form, which, 

 it would seem, however, is closely related to Tedania. The 

 spiculation of the two genera separates them, though the 

 occasional presence of tylotes in Tedanione coupled with the 

 great similarity in the canal system and histological structure 

 makes a close kinship between the two very probable. 



Diagnosis of Gams. — Spicules mostly o.xeas, with micros- 

 cleres of same pattern, and a very few tylotes. Flagellated 

 chambers open directly into afferent and efferent canals. 



Tedanione foetida, n. sp. — Sponge amorphous with two or 

 three cylindrical oscular papillae one inch high. Size, rarely 

 over three inches from osculum to base. Sponge is slatebrown, 

 has a fetid odor in life, and the surface is irregularly and incon- 

 spicuously furrowed. Main efferent canals surrounded by large 

 amount of gelatinous tissue which only occasionally comes to 

 the surface. Pores rare and scattered. Subdermal cavities 



