PLATE LXXXIX. 



membrane mounted in Canada balsam the pores were 

 seen to be irregularly dispersed ; they were rather 

 large, comparatively, and were in an open condition. 



The dermal membrane abounds in its characteristic 

 spicula. The tension ones are quite as large, and of 

 the same form as those of the skeleton ; and the re- 

 tentive ones are also abundant. They appear to be all 

 nearly equal in size, and when in situ they are attached 

 by the middle of the back of the shaft of the spiculura 

 so as to project both the anchorate terminations from 

 the membranous surface to which they are attached. 



The skeleton columns are slender but compact in 

 their structure, branching at intervals and winding 

 irregularly towards the surface of the sponge. The 

 internal defensive spicula, projected from the columns 

 in every direction, are exceedingly numerous and many 

 of them are comparatively very large and long ; some 

 of them are profusely spinous, the spines being stout 

 and conical; while in others the spination is much 

 more delicately produced. 



This species is closely allied to M. fiditia, and might 

 readily be confounded with that species by a hasty ob- 

 server; but the forms of the skeleton spicula will 

 always distinguish them. In M. flctitia those organs 

 are purely acerate, while in M. Kentii they are strikingly 

 fusiformi-acerate ; they differ also in comparative size, 

 their lengths are in the former to the latter as seven 

 to four. The retentive spicula of the two species are 

 very similar in form ; but they are larger and very 

 much stouter in M. fiditia than in M. Kentii. I have 

 named this species after my friend Mr. W. Saville 

 Kent, to whom I am indebted for my knowledge of it, 

 and for many other interesting British sponges, the 

 result of his dredging expedition in 1870 in the yacht 

 Norna, with Mr. Marshall Hall. 



I have subsequently found among the sponges 

 dredged by the Rev. A. M. Norman at Jersey three 

 specimens of the species in a much finer condition 

 than the type-one found by Mr. Kent. None of the 



