190 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
is an enormous accumulation of digestive glands, in the form of a belt 
round the base of the pharynx. The parenchyma proper consists solely 
of cells with prolongations which intermingle and bound lacunar 
spaces. 
The pharynx is placed in a pouch, and is covered externally and 
internally by an epithelium which is formed of distinct cells which are 
provided with pores and are, in places, ciliated. Mucous and salivary 
glands, the latter of which have not hitherto been detected, are to be 
distinguished. In the three species examined the intestine has no 
proper musculature, the place of which is taken by some of the dorso- 
ventral muscular fibres. The author thinks it very probable that the 
excretory system communicates with the exterior by canals which pass 
into the pharynx. 
Fertilization is effected in the uterus, which is lined by large 
glandular cells, the secretion of which aids in forming the cocoon. The 
brain consists of an upper sensory portion, formed of two ganglia united 
by a commissure, and an inferior motor of similar constitution. The 
brain of P. montana is intermediate between the simple organ of 
P. polycliroa and P. lactea and that of Gunda segmentata which is 
differentiated into two distinct parts. 
Turbellarian Fauna of Moscow.* — Mr. W. Zykoff has a short note 
on the Turbellaria found in the neighbourhood of Moscow. He adds 
seven to the fourteen species already known. Derostoma unipunctatum 
has been found in large numbers ; of the many specimens of D. Cyclops 
the majority have the anterior end colourless; the only other place 
where this species has been found is Prague. A species allied to 
Mesostoma personatum , but distinguished from it by a constriction at 
the anterior end and by the form of its spots, is referred to, but not 
named. Only one species, Polycelis niger , of Dendrocoela has as yet been 
found near Moscow. 
Pelagic Poly clads, f — Prof. L. Graff gives an account of a few 
pelagic Polyclads which he has had the opportunity of observing. They 
are all characterized by the pellucid nature of their body, in which 
but little pigment is deposited. Planocera Grubei and P. SimrotM are 
remarkable for the slight differentiation of the brain, and in the latter 
species there is a decentralization of the nervous system. P. SimrotM 
affords the second example of the absence of an antero-median branch of 
the enteron extending over the brain of a Polyclad, and the same species 
has allowed of the observation that, as Lang has already stated, the 
ovaries are derived from the enteric epithelium. It also serves very 
well to show the relations between the form and position of the nucleus 
and the secretory activity of the cells which form the penial spines. 
In P. pellucida and P. SimrotM the oviduct lies in front of the shell- 
gland, whereas in all other Polyclads the relation of these two struc- 
tures is reversed. The presence of sperm in the accessory vesicle of 
the female generative apparatus of Stylochoplana sargassicola and Plancto- 
plana cJiallengeri calls to mind a similar observation in Enantia spinifera , 
and indicates that the accessory bursa is probably, in most, if not all 
* Zool. Anzeig., xv. (1892) pp. 445-7. 
f Zeitschr. f. Wise. Zool., lii. (1892) pp. 189-219 (4 pis.). 
