DR, A. FARRE ON THE STRUCTURE OF THE CILIOBRACHIATE POLYPI. 399 
being- straight and not folded on itself, and the body being unshackled by a dense co- 
vering, the parietal muscles alone are adequate to effect its expansion. 
Upon a review then of this description of the organization of .Bowerbankia, it must 
be admitted that the mechanical functions are executed with a degree of perfection, 
which in a being so exceedingly minute cannot fail to excite our surprise and admi- 
ration : not less interesting either is it to observe the more vital operations of this 
highly organized species. 
The little animal, when in full vigour, is seen projecting from its cell with the arms 
extended and the cilia in full operation, the upper part of the body being frequently 
turned from side to side over the edge of the cell, the extremity of which, from its 
peculiar flexibility, moves along with it. The particles, carried to the mouth in the 
vortex produced by the action of the cilia, after remaining a little while in the pharynx, 
are swallowed by a vigorous contraction of its parietes, and carried rapidly down the 
oesophagus and through the cardia to the gizzard, which expands to receive them. 
Here they are submitted to a sort of crushing operation, the parietes of the organ 
contracting firmly upon them, and the two dark bodies being brought into apposition. 
Their residence, however, in this cavity is only momentary, and they are immediately 
propelled into the true stomach below, where they become mixed up with its contents, 
which during digestion are always of a dark rich brown colour, being tinged by the 
secretion of its parietal follicles. 
The food appears to be retained for a considerable time in the stomach, and may 
be frequently seen to be regurgitated into the gizzard, whence, after having been 
again submitted to its operations, it is returned to the stomach. Here it is rolled 
about by the contraction of its parietes, and at its upper part is frequently submitted 
to a rotating motion. This rotation of particles is chiefly near the pyloric orifice, and 
a mass may be frequently seen projecting through the pylorus into the intestine, and 
rotating rapidly in the direction of the axis of the orifice. In an animal having a 
similar form of pylorus to this, but in which the parts were more transparent, I could 
distinctly see the cilia by which this rotation is effected surrounding the orifice. 
The granular matter, after rotating for some time at the pylorus (a provision for 
preventing its too rapid escape from the stomach), passes into the intestine, where it 
accumulates in little pellets, that distend the parietes of the tube ; and it is possible 
that it may be here still further acted upon by these parietes, which have a spotted 
appearance. 
By the contraction of the intestine the little pellets of excrementitious matter are 
carried rapidly upwards to the anal orifice, which is seen to open, and the little pellet 
to be tilted over its edge, when it is immediately whirled away from the sight in the 
current produced by the ciliated tentacles, and the orifice of the tube again contracts. 
With regard to the mode in which the animals are united together, I could not dis- 
cover that any connection existed between them beyond that which results from their 
cells being placed upon a common stock. In almost every case, however, I could 
