54 THE ANATOMY OF AN AUSTRALIAN LAND PLANARIAN. 
enclosed in a cyst ‘‘ au milieu des fibres musculaires rayonnantes du pharynx de la 
Planaria nigra et du Dendrocoelum lacteum,” so that it appears that both terrestrial 
and aquatic Planarians are subject to these parasites. 
EXTERNAL CHARACTERS. 
The worm under consideration is a fine, handsome Planarian, some idea of the 
size and general appearance of which may be gathered from figures 1 and 2, which 
were drawn by myself from the living animal. Well-grown specimens, after 
preservation in alcohol (Fig. 3) measure about two inches in length, and are rather 
broad in proportion to their length as compared with many species. When crawling 
about, however, the worm elongates itself greatly, and the body becomes 
correspondingly slenderer.* 
The dorsal and ventral surfaces of the body are very distinctly marked off from 
one another, the dorsal surface in the living worm being of a uniform, very dark olive 
green colour, almost black, and the ventral surface a beautiful cobalt blue. The 
colour of the dorsal surface is continued ventrally so as to form a narrow edge of dark 
olive green all round the ventral surface, which is much flattened. 
The extreme anterior tip of the animal has a distinct brownish pink colour; it 
tapers off considerably in front and, as I have already pointed out, is uplifted from the 
ground when the animal is moving about, as would seem to be the case in all land 
Planarians. 
The minute aperture which leads into the peripharyngeal chamber is placed 
nearly in the centre of the body in the mid-ventral line. The pharynx (Fig. 3, pi.) 
is a large organ of a creamy or white colour. When protruded it is seen to be 
cylindrical, terminating in an expanded, disk-like sucker, which has a small 
perforation—the true mouth—in its centre. | 
The common genital opening is situated about half-way between the opening into 
the peripharyngeal chamber and the posterior end of the body, also in the mid- 
ventral line. 
The eyes are distinctly visible with a pocket lens, as small dark specks, at the 
anterior end of the body. Their exact position was determined by means of sections, 
and will be described subsequently. 
InteRNAL ANATOMY AND HistToLoey. 
A.—The Epidermis.—In ordinary microscopical sections of material preserved 
simply in alcohol it is, as already noticed by Moseley (6), very difficult, if not 
impossible, to make out satisfactorily the structure of the epidermis. Sections taken 
from an animal killed with hot corrosive sublimate, and cut by the paraffin method, are 
eee During my visit to Walhalla I found a number of very large specimens, some of which must have been fully 
six inches in length when crawling. 
