SPECIES OF PLANARIAN WORM. 35 
specimen could not be entirely sacrificed to the microtome. I 
content myself therefore with giving a short sketch of some of 
the more important anatomical features which could be gathered 
from a careful examination of the sections. The head and a 
portion of the body containing the pharynx were cut into trans- 
verse sections, whilst a small part bearing the genital pore was 
utilized for longitudinal ones. From these the following obser- 
vations were noted :— 
One of the most striking objects in the series of sections near 
the anterior end of the body is the pair of eyes. If we 
examine such-a section more closely (Pl. 6. fig. 3), we notice 
externally the epzdermis (ep.). Some previous writers, especially 
Prof. S. Moseley (4) and Dendy (1), have referred to the great 
difficulty in obtaining a clear idea of the structure of this layer 
from ordinary cross sections. My single specimen, as already 
stated, had not been fixed in a satisfactory manner for histo- 
logical purposes. But whatever method is employed for fixing, 
the chief difficulty in recognizing the structure of the epithelium 
_ ‘lies in the fact that the greater part of it is filled with rod-like 
bodies, while numerous glands open between the cells to carry 
- their secretions to the exterior. The epithelium consists of a 
single layer of cells which, in this part of the body, are about 
equally high on the dorsal and ventral surface. The sole (s)— 
von Graff's “ Kriechleiste ”—possesses a ciliated epithelium, but 
cilia appear to be confined to this part of the under surface, 
The most noteworthy features in connection with this sole are the 
sensory grooves (sq.), which I failed to make out from a macro- 
scopic examination of the worm. They are probably united in 
front in the form of a horseshoe, the two branches being con- 
tinued backward for a little distance beyond the eyes on each 
‘side of the sole. These sensory grooves have been demonstrated 
in the great majority of Land-planarians by Prof. von Graff. As 
a rule there are also sensory pits in connection with the grooves, 
but according to the same author (2. p. 42) these are absent in 
Rhynchodemus bilineatus, Rh. Scharffi, Rh. nematoides, and Rh. 
ochroleucus. No trace of such pits could be seen in the cross- 
sections of Rh. Howesi, so that it agrees in this respect with 
some of the other species of the genus. 
Almost all previous writers on the Land-planarians have 
referred to the peculiar rod-like “ Rhabdites,” which have becu 
compared to the stinging-organs of Ceelenterates, but whose 
a 
