300 PLATE LXXXVJ. 



in fig. 14 from a specimen of the sponge from Bombay 

 presented to me by Mr. Carter many years since. 

 The rotulate spicula of the ovaries of S. Parfitti very 

 closely resemble those of 8. fluviatilis, but they are 

 rather smaller; the skeleton spicula are also rather 

 smaller than those of 8. fluviatilis. Fig. 16 is of 

 exactly the same size and form as those of the last- 

 named species, so that a comparison of fig. 16 with 

 figs. 8 and 9 represents the proportional differences 

 existing between the two species under consideration. 

 The greater number of the rotulate spicula in 8. 

 Parfitti are like that represented by fig. 11, and this 

 appears to be the normal form. The larger one with 

 the spiculated shaft, represented by fig. 10, is of com- 

 paratively rare occurrence. 



SPONGILLA SCEPTKIFERA, Bowerbanlc. 

 Plate LXXXVI. 



Sponge massive, sessile. Surface smooth and even. 

 Oscula simple, large. Pores inconspicuous. Dermal 

 membrane pellucid, abundantly spiculous ; spicula 

 acerate, very minute, and sceptriform spicula with 

 bulbous terminations ; bulbs of unequal size, very 

 minute. Skeleton. Reticulations rather close and com- 

 pact, but slender ; spicula acerate, rather large. In- 

 terstitial membranes. Retentive spicula slender and 

 very minute, few in number. Ovaria unknown. 



Colour. Dried state, light fawn yellow. 



Habitat. On Anacharis alsinastrum in one of the 

 Exeter reservoirs ; Mr. Edward Parfitt. 



Examined. In the dried state. 



We are indebted to the acute discrimination of Mr. 

 Edward Parfitt, of Exeter, for our knowledge of this 

 interesting addition to the list of our British spon- 

 gillas. He found one specimen only growing on 

 Anacharis alsinastrum, the one represented by fig. 15, 



