ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
461 
j 8- Nemathelminthes. 
Lemnisci of Nematodes.* — Dr. 0. Hamann has come to the con- 
clusion that there is a complete homology between a whole series of 
organs in Nematoda and Acanthocephala. The lemnisci of the latter, 
the history of which is so obscure, are to be found in Nematodes, where 
they have been called cephalic or cervical glands. These so-called 
glands are, in Dochmius duodenalis and all Nematodes which possess 
them, continuations of the dorsal and ventral longitudinal lines, just 
as the lemnisci of Echinorhynchus are continuations of the skin. The 
history of their development has shown that the subcuticula of Nema- 
todes with its four outgrowths (so-called lateral or longitudinal lines) 
represents the epidermis, and is formed from the cellular ectoderm of 
the larva. The water- vascular system of Echinorhynchus is homologous 
with that of Nematodes. In both groups it lies in the skin (ectoderm), 
and has two longitudinal vessels, which, in the Nematodes, run in the 
dorsal and ventral longitudinal lines. There are also in the epidermis 
of Nematodes afferent canals of very various kinds, as well as structures 
which call to mind the lacunae in the skin of Echinorhynchus. 
The gigantic spherical nucleus, nearly 0 * 1 mm. in size, found in the 
lemnisci of Nematodes, is seen in Echinorhynchus clavseceps , and some- 
what modified in E. clavula , E. tsenioides, E. spira , and others. In both 
groups the lemnisci arise as projections from the epidermis into the 
body-cavity ; they grow backwards and become finger-like and saccular 
organs, which in the simplest case merely contain a cavity or sort of 
canal. The lemnisci are, then, direct continuations of the skin, and there 
is no question as to the absence of an orifice. Not only can the ectodermal 
vascular system be shown to be homologous in the two groups, but the 
same is true of the body-cavity. In both there is a true coelom lined by 
an epithelium. The polyhedral cells of this layer may, in either group, 
give rise to muscular fibrils, but in most members of both groups the 
epithelium disappears. On the whole, there is good reason for supposing 
that the Acanthocephala, of which Echinorhynchus is the representative, 
are not to be separated from the Nematodes. 
New Nematode from a Galago. t — Prof. P. J. Van Beneden gives a 
description of a new Nematode, which he calls Strongylus otolicni , found 
in the caecum of Otolicnus peali. It is about 15 mm. long, and 0*75 mm. 
thick ; males and females were found in about equal numbers, and the 
latter do not appear to be viviparous. 
Development of Strongylus strigosus and S. retortseformis.J — 
Prof. A. Railliet has made some experiments on rabbits which prove 
that these two nematoids follow Leuckart’s law, and develope without 
any intermediate host. The former is found in the stomach, the latter 
in the stomach also, but chiefly in the small intestine. 
* Zool. Anzeig. xiii. (1890) pp. 210-2. 
f Bull. Acad. Roy. de Belgique, lx. (1890) pp. 889-93 (1 pi.). 
X Bull. Soc. Zool. France, xiv. (1889) pp. 375-7. 
