

TRANSACTIONS OF THE SECTIONS. 73 
covered by the glutinous substance, which when dried forms the cement and tubing 
of the case. With its mouth the creature places the sand upon its back and then 
rolls itself from side to side, and again puts forth its tentacula in search of fresh ma- 
terial. The whole internal cavity of the worm in which the viscera exist is filled by 
a fluid, by which the animal has the power of moving, the loss of which entails de- 
struction of all motive power; to preclude which circumstance, upon receiving any 
external wound, the animal will divide itself by contraction of the annular muscles 
anterior to the wound, which operation it will also perform in order to escape from 
the grasp of an enemy. 
From the head of the animal to about the lower extremity of the stomach is a mass 
of white granular material, which the author presumes to be the ovaria, on either 
side of which are ducts leading into several pear-shaped sacs. Early in February 
the author noticed active motion of the fluid within passing in one direction, excited 
by a powerful set of cilia; shortly after some-particles of the fluid existing within these 
sacs seemed to unite together, which became the earliest formation of a new creature; 
this little animal exists by the introduction within its own system of the parent fluid 
by which it is surrounded; this is done through a circular umbilical pulsating heart 
which opens by a slit, situated about: the centre of the young creature. Shortly after, 
what the author has termed umbilical circulation ceases, and the young worm moves 
within the uterine sac; as the creature progresses the intestinal canal also becomes 
more perfect, and shortly after it leaves the sac and enters into a passage or oviduct, 
one of which on either side traverses the walls of the parent and opens into the rectum 
beyond the point where the intestinal tube is incorporated with the outer walls of the 
worm, and there voided. 
Sabella alveolata (Hermella, Savigny)—After speaking of the habits of this an- 
nelide and the circulatory system, the author says, in relation to the organs of pro- 
gression, besides all these there are other setz situated upon the back; these perform 
a most important office in the ceconomy of these creatures, which is to eject from the 
cell the fecal matter; that this may be accomplished the more easily, the intestinal 
canal is extended beyond the creature, making a sort of tail about one-fourth of the 
whole length of the animal, which is turned forward upon the dorsal surface; the ex- 
pelled material is taken up by these delicate setze and passed forwards from one to 
the next until it reaches the entrance to the abode, where, when under water, it is 
ejected with considerable force, but at other times it is deposited at the entrance and 
washed away by the first passing wave. 

Notes on the Boring of Marine Animals. By C. Spence Bate. 
The latest theory which, possessing novelty, has. been advanced, is that of Mr. 
Hancock (Brit. Association, Swansea, 1848; and Annals of Nat. Hist. October 1848), 
Prof. Forbes at the same meeting stated, that “he endeavoured to find the crystalline 
spiculze (with which the author affirms the foot tobe armed for boring), but without 
success, either by the aid of the microscope or by chemical tests.” 
Throughout his paper Mr. Bate accepted the presence of these crystalline bodies as 
a thing proved, and endeavours to show that the holes dwelt in by marine animals 
could not owe their existence to any mechanical force by a creature so armed and 
formed, even supposing the rock sufficiently soft to be mechanically fretted away. 
Yhe author of this paper noticed a hole so deviating from the cylindrical in figure, 
that a prominent portion of the matrix projects so as to occupy a position between 
the anterior edge of the two valves. This fact he argues is in opposition to either of 
the three theories which naturalists have most favoured. 
First. It is opposed to the theory of mechanical attrition by an armed foot, since 
the greatest protuberance exists in juxtaposition with the aperture in the mantle 
through which the foot must extend itself, and is thus sliown to be inefficient for the 
purpose, 
nilly. To that advanced by Mr. Osler, that part which is nearest the foot and 
consequently the most liable to be acted upon, is the least so. 
Thirdly. To that which presumes that the animal wears the rock by the means of 
its own shell, using it upon the principle of an auger; since the presence of such an 
irregularity precludes the possibility of either valve from moving ventrally forwards, 
and consequently from a rotatory motion. 
