336 Mr. A. Hancock on tJie Excavating Powers of Sponges, 



I have seen only one specimen of this interesting species ; it 

 occurs in the shell of Monoceros fusoides in the Newcastle Mu- 

 seum. It has injured nearly the whole surface of the body- whorl, 

 and has extended its ravages over most of the spire. 



C. Howsei. PI. XIV. fig. 8. 



A small delicately branched and closely anastomosing species 

 with the branches slightly lobed or nodulous : terminal twigs 

 slender, long, linear, and rather acutely bifurcating, and anasto- 

 mosing widely for a considerable length backwards ; afterwards 

 "the meshes become very much reduced in size by the addition of 

 branches. In the older parts, where the anastomosis is very dense, 

 the meshes being about y^th of an inch wide, the lobes or no- 

 dules are most distinct ; they rarely exceed y^^th of an inch in dia- 

 meter : papillae very fine and close-set, running in a single row 

 along the branches, and generally so disposed that the anasto- 

 mosis can be easily followed by the perforations they make in the 

 surface of the matrix, but from their minuteness might readily 

 escape observation. Spicula very delicate and about y^o^h of an 

 inch long ; there are tw^o kinds ; one is generally straight and 

 tapers to a very fine, slender point at one end, and has at the 

 other a well-marked terminal head, which is short and broadly 

 ovate, with the apex at the extremity, and sometimes a little pro- 

 longed: the other kind of spicula is generally a little longer 

 than the preceding, and is mostly somewhat bent, but is likewise 

 slender and gradually diminishes to a fine point at one extremity ; 

 the other is most commonly furnished with two heads ; one is 

 terminal or nearly so, the second is placed about |^rd down the 

 shaft : it also frequently happens that the terminal head is 

 wanting. 



This species is so very distinct in all its characters, that it 

 cannot well be confounded with any other British form. Its 

 slender, delicate branches, small and regular papillary punctures 

 arranged in anastomosing lines, and its characteristic two-headed 

 spicula at once distinguish it. Only two specimens have occurred, 

 one in Fusus antiquus from the Dogger-bank, the other in a 

 nullipore procured from the beach at Tynemouth. For these 

 and for several other specimens I am indebted to Mr. Richard 

 Howse, after whom this species is named. 



C. Northumhrica. PL XIV. fig. 5. 



Sponge when dry of a pale yellow colour, branched, closely 

 and irregularly anastomosing and indistinctly lobed ; the larger 

 lobes being sometimes ^th of an inch across : papillse rather 

 small, seldom more than ^\jth of an inch in diameter, placed 

 considerably apart along the branches, but appearing numerous. 



