DEC 1 ] 1901 
THE 
I — Notes on Bucephalus polymorphus. 
By Chas. Stewart, F.L.S., Hon. Sec. R.M.S., &c. 
( Rend before the Royal Microscopical Society, . Tune 2, 1875.) 
Plate CVIT. 
Through the kindness of Mr. Badcock I have had an opportunity 
of examining that curious animal Bucephalus polymorphus, which 
has lately been exhibited at this and other Societies. I regret that 
I have only some slight notes to offer on its structure, and can add 
nothing to our knowledge of its life history. 
The Bucephalus consists of three parts, viz. two spheres, two 
appendages borne on these, and a central main body. The spheres 
are hollow and contain granules which freely move from one to the 
other. In shape each resembles a peach, with the part corresponding 
with the cleft of the fruit and point of insertion of the stem, .repre- 
sented by a smooth area facing the central body of the animal, and 
extending to their outer sides where the appendages are attached'; 
the remaining part of the spheres presenting a rough warty aspect. 
The appendages are densely filled with minute granules, most 
abundant near their surface, hut in their interior mixed with 
numerous transparent spherules. The appendages are in a constant 
state of contraction and expansion, their extremities often suddenly 
curling round and forming a spiral of from two to three turns. The 
contraction of the appendage in length is accompanied by a synchro- 
nous contraction of the sphere at its base, which forces its contents 
for a short distance into the appendage, although a thin membrane, 
which prolapses, appears to separate their cavities. As might be 
expected, when the appendage elongates the sphere dilates and the 
contents of the appendage prolapse into it. 
The. movements of the central body are not so energetic as those 
of other parts, and resemble those of a leech when it is fixed by its 
EXPLANATION OF PLATE CVIL 
Fig. 1 . — Bucephalus polymorphus. 
„ 2. — Three layers of central body. 
„ 3. — Optical section of ditto. 
,, 4. — Front of body. 
„ 5. — Side view of ditto. 
VOL. XIV. 
B 
