336 Mr. A. Hancock on the Excavating Powers of Sponges, 
I have seen only one specimen of this interesting species ; it 
occurs in the shell of Monoceros fusoides in the Neweastle 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. Pl. 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 ;4,th of an inch wide, the lobes or no- 
dules are most distinct ; they rarely exceed =4,th of an inch in dia- 
meter; papillz 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 ;4,th of an 
inch long; there are two 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 5rd 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 oceurred, 
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. Northumbrica, Pl. XIV. fig. 5. 
Sponge when dry of a pale yellow colour, branched, closely 
and irregularly anastomosing and indistinetly lobed ; the larger 
lobes being sometimes 3th of an inch across: papille rather 
small, seldom more than =4th of an inch in diameter, placed 
considerably apart along the branches, but appearing numerous, 
