SPONGES. 269 



characters, can, nevertheless, be recognized by peculiarities of 

 form and other features of minor importance. For these we 

 propose the varietal names pistilliformis, turbinata and sub- 

 rotunda. 



var. PISTILLIFORMIS U. & E. 



PL V, fl. 4. 



This variety is distinguished from the typical form of the 

 species by having a more distinct stem, the radiating channels 

 less regular, and oftener united by inosculation, the vertical 

 cloacal tubes somewhat larger and much less numerous, and 

 the upper surface convex instead of flat. The three specimens 

 referred to the variety are also smaller, the largest being only 

 36 mm. high, while the greatest diameter is 35 mm. 



var. TURBINATA U. & E. 



PL V, Fie. 3, Sa, 3b, 3c. 7. 7a. 



The turbinate form of the sponge is the distinguishing charac- 

 ter of this variety. In all other respects a close resemblance to 

 the typical form prevails. Six specimens are referred to the 

 variety. The two examples, illustrated on plate V, are of 

 medium size. 



var. SUBROTUNDA U. & E. 



PL V, Fte. 2, 2a. 



This form is related to var. turbinata, but differs from it, and 

 to a greater degree from var. pistilliformis, and the typical 

 form of the species, in the subglobose body of the sponge. The 

 central or cloacal depression is deeper than usual, and it does 

 not appear that the sponge was prolonged below into a stem. 



We have seen only two specimens which could be referred to 

 this variety, and both are much worn and imperfect. In their 

 present condition they present very little resemblance to Z. 

 typicalis, but fearing the differences might in part be due to the 

 poor state of preservation, and as the var. turbinata is an in- 

 termediate form, we preferred to class them as above. 



