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NE ERED EE EIS DEL IOI SE IN 
342 Mr. A. Hancock on the Excavating Powers of Sponges, 
oval, and occasionally irregularly angulated lobes about ;5th of 
an inch wide, and united by a small central stem : terminal twigs 
short, linear, and bifurcated: papille small, numerous, and dis- 
tributed on the surface of the matrix without apparent order. 
Spicula ;45th of an inch long, not very slender, mostly a little 
bent, and brought gradually to a sharp pomt at one end; the 
other with an irregularly rounded head, sometimes slightly ellip- 
tical, and generally not exactly terminal. 
The puncturing of the chamber-walls of this species is strong 
and decided, and the branches in old specimens are much con- 
fused on account of the frequent anastomosis and the crowding 
caused by the lobes. Towards the terminal twigs the character 
of the branches is however quite distinct. The C. lobata is not 
to be confounded with any other of the British forms, and is 
undoubtedly distinct from the various foreign species that have 
come under my notice. It occurs in Haliotis from. Guernsey. 
I have seen two specimens affected by it, and in both cases very 
extensively ; in one the whole external surface is crowded with the 
minute papillary punctures. 
C. vastifica. Pl. XV. fig. 12. 
Sponge formed of a close and intricate anastomosis of strongly 
lobed branches ; lobes irregularly angulated, frequently 3th of an 
inch wide, and united by a delicate stem : terminal twigs not long, 
linear : papille small, rarely exceeding =4,th of an inch in dia- 
meter, very numerous, close-set, and pretty regularly distributed 
over the surface of the matrix. Spicula of two kinds, one much 
larger than the other; the former ,,th of an inch im length, 
straight, rather slender, and diminishing imperceptibly to a very 
fine point at one end; the other terminating in a perfectly glo- 
bular head. The smalier kind of spiculum is about {rd the 
length of the larger, and is much thinner; it is stoutish in the 
centre, where it rather suddenly bends a little, and from thence 
tapers gradually towards the ends, which are sharply pointed. 
When the outer surface of the shell containing this species is 
removed, a complete close network of chambers is revealed, con- 
taining the lobes of the sponge ; and on a closer examination they 
are seen to be united by small circular passages for the accom- 
modation of the uniting stems. The only specimen I have seen 
of this species is in the shell of an oyster from Prestonpans ?, the 
surface of which had suffered much injury by the influence of 
this parasite. The puncturing of the sides of the cavities of this 
species is finer than usual. 
C. rhombea. Pl. XII. fig. 7. 
Sponge when dry of a pale straw colour, composed of nume- 
