600 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
is the komologue of the packet of rod-forming and mucus-producing 
glands which open at the anterior end in many Turbellaria. 
The Zoochlorellse of Convoluta are Algar in nature, and this worm 
exhibits in a high degree the phenomena of symbiosis. 
Nervous System of Monocotylidea.* — M. G. Saint-Remy has ex- 
amined the disposition of the nervous system in Pseudocotyle squatinae 
and Microbothrium apiculatum. He gives a detailed account of the 
former, which is not unlike that which is found in the Tristomidae. In 
the latter it is more complicated than in any observed member of the 
group. The brain, which is greatly reduced, gives off anteriorly two 
branches, which correspond to the first pair in the Tristomidae. 
Posteriorly it is prolonged on either side of the pharynx into a branch 
■which goes to the pharyngeal ganglion, and gives off two small branches 
which are, perhaps, homologous with the second and third pairs of 
Pseudocotyle. The pharyngeal ganglia are two large masses connected 
by a transverse branch ; from this last there arises a pair of very short 
nerves which correspond to the later dorsal nerves of the Tristomidae ; 
two ventral longitudinal nerves are given off from each ganglion as well 
as two accessory nerves which are lost in the parenchyma. Lastly, 
from the extremity of the nerve there is given off an anterior nerve, 
which seems to be a continuation of the external ventral nerve; it 
extends as far as the mouth, and on its way unites with the branch 
which goes from the brain to the pharyngeal ganglion ; this nerve 
appears to represent the third anterior pair of the Tristomidae. The 
two ventral nerves are connected with one another by commissures as 
in Pseudocotyle. On the whole the nervous system of Monocotylidea 
exhibits an unexpected complication of the plan seen in the Tristomidae. 
Hymenolepis.'f — Prof. R. Blanchard gives a zoological and medical 
account of the Taeniidae of this genus, to which belongs the minute form 
oiten called the Taenia nana of Man; the author gives a full description 
of the structure and development of this parasite, and also deals fully 
with H. diminuta. The fourteen species of the genus are divided into 
two groups — one armed and one unarmed. The chorology of the species 
is also discussed. 
5. Incertse Sedis. 
Contribution to the Study of Rotifers. J — M. J. Masius gives some 
details, without any generalizations, as to the structure of Asplanchna 
Helvetica and Lacinularia socialis. Of the points described we may note 
that, in the first, the author observed the evaginated pharynx, where he 
was able to distinguish two large contractile cells with prolongations ; 
these last were so distributed as to surround the pharynx with a kind of 
contractile plexus. Between the stomach and the hinder end of the 
body there is a cell of connective tissue ; this cell is stellate, and its 
prolongations are directed in opposite directions and are inserted, 
some into the outer surface of the base of the stomach, others into the 
cuticle of the end of the body, and others into the generative apparatus. 
* Comptes Rendus, cxiii. (1891) pp. 225-7. 
t ‘ Histoire zoo ogique et medicale des Teniades du genre Hymenolepis Wein- 
land,’ Parid, 1891, 8vo, 112 pp., 22 figs. 
; Arch, de Biol , x. (1891) pp. 651-82 (2 pis.). 
