232, LIVERPOOL BIOLOGICAL SOCIETY. 
tective colouring to enable them to escape from their 
enemies ; what they really want are warning colours. __ 
The dimensions of the largest specimen of Pachymatisma 
from Puffin Island is 10 cm. by 7 cm. in horizontal direc- 
tion; 1°5 cm. in height. The largest specimen from Port 
Erin measures 12 cm. by 6 cm. horizontally and 6 cm. 
vertically. I give also the measurements of the spicules, 
as my results differ somewhat from Bowerbank’s and 
Sollas’s * :— 
I.—Megasclera: strongyla, 0°57 to 0°75 mm. by 0°012 
to 0°024 mm. Orthotriena: rhabdome, 0'405 by 0-016 
mm ; Cladus, 0°255 by 0°016 mm. Also a few styl are 
present, which are not mentioned by Bowerbank and 
Sollas. They measure 0°635 by 0°009 mm. 
I1.—Microsclera: sterraster, either spherical, 0°045 to 
0:075 mm. in diameter; or elliptical, from 0:06 by 0°045 
mi. to 0°09 by 0°068 mm. Oxyaster, 0'048 to 0°056 mm. 
u diameter; microstrongyla, 0°018 by 0:003 mm. 
This species seems to be the only tetractinellid sponge 
which up to now has been found at the Isle of Man, and 
it is now for the first time recorded in our L.M.B.C. 
reports from that locality. I hear that Mr. Geo. Swainson, 
of Bolton, collected some specimens of it at Parwick Bay, 
Isle of Man, during last autumn. 
Order VI. CALCAREA. 
Asceita coriacea, Fleming. 
I found a single small specimen of this species at Puffin 
Island, April, 1889, at lowest spring tide, in the large cave. 
on the north side of the island. It encrusted a living 
oyster, which latter was firmly attached to the wall of the 
cave. 
* Sollas, loc. cit., p. 242. 
a 
