152 
Description of a Sea Stuff. 
We are commencing a new and important era in palaeontology, 
which will demonstrate a wonderful and very extensive, but by 
no means exclusive , agency of animalcules in the formation of 
limestone. In the case of crystalline marbles, it is probable 
that, if any organic remains were ever contained in* them, they 
have been obliterated by heat. 
SEA SLUG. 
Description of a Sea Slug found at Port Arthur, by T. 3', 
Lempiiere, Esq., D.A.C.G. 
The colour is jet black. If the animal is placed on a sheet 
of paper, the black will adhere thereto ; and the part thus un¬ 
covered has the same appearance as the flesh of fish in general. 
The size—seven inches in length, and, when the flaps are 
distended, the same width. If the flaps are folded on the 
back, the breadth is reduced to three inches. The head is two 
inches long that is, when extended—from mouth to insertion 
of the flaps, and is two inches thick. The front of the head 
is square; and on each side of the mouth are auriform tentacular 
On the top of the head, one inch and a half from the front, are 
two tentaculae, one inch long, of a spiral form. 
On the back two large soft flaps (in the shape of the wings 
of some of the Coleoptera tribe of insects) meet, giving the 
animal then a globular appearance : these sometimes lie flat 
to the sides. Under the flaps a disk of a harder substance is 
seen, the hardness of which is caused by a leaf-shaped trans¬ 
parent cartilage: this disk is connected with the animal on the 
left side ; on the right side it lifts upland discovers a papilosc- 
substance, beneath which, covered by a pellucid skin, the in¬ 
testines are perceived. The under part of the animal is 
papilose. 
The mouth is flesh-coloured, and furnished with hard labia. 
A semi-transparent and globular substance I took for the 
tongue. The aperture of the throat is rough, like a flue file. 
1 he roots of the top tentaculm are closed together, although, 
on the outside of the head, they appear an inch apart. About 
three inches from the head the canal enlarges, and is formed 
tor the space of three quarters of an inch of apparently a hard 
fleshy substance: on opening this part, I found it to contain- 
from twenty to thirty small objects in the shape of four-sided 
cones, of various lengths, some measuring as long as a quarter 
of au inch from base to apex ; the base slightly adhering to the 
flesh. They were semi-transparent, of an amber colour, and 
father hard ; on drying them, they shrank nj>. 
