ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
41 
testes ; the spermatozoa are short thick rods, one-half of which is thinner 
than the other. The ovaries of young females are organs tilled with 
cells, which begin just behind the head, and soon become so large that 
they nearly fill up the spice in the body. Tiie structure of the gonads 
of both sexes is described in some detail. The external cojuilatory 
organs described by Vejdovsky do not seem to exist in G. tolosanus ; the 
“ bursa ” would appear to be a hardened mass of sperm, and the cirrus 
an artifact. 
Dr. Linstow thinks that the Gordii are allied to the Annulata by 
the segmentation of the cell-body and of the ovaries, by the double 
nature of the male organs, and the ventral position of the nerve-cord ; 
while, on the other hand, their developmental history, as lately described 
by Camerano, allies them to the Nematodes. 
Notes on Mermis.^ — As a continuation to the above. Dr. v. Linstow 
offers some notes on Mermis. He gives descriptions of the new aquatic 
forms which he calls If. contorta and 31. crassa. The former is very 
elongated and thin, the male being 14*8 mm. long, and 0*17 broad, 
while females were found which measured 24*1, 42, 44-8, and 49 mm. 
with the respective breadths of 0*23, 0*28, 0-26, and 0*28 mm. In 
the median axis of the oesophagus there is a strong chitinous tube. 
31. crassa is much more robust then 31. contorta, and offers some 
important anatomical differences from ilf. albicans and 31. nigrescens. 
The cuticular stratum consists of four layers — a fine, homogeneous epi- 
dermis, a superficial corium in which two systems of fibres cross one 
another, a somewhat thicker corium-layer which consists of circular 
fibres, and a fine hypodermis. Six very well-developed longitudinal 
ridges extend through the whole length of the body ; they are due to 
thickenings of the hypodermis, and are best developed in the region of 
the head. The musculature breaks up into six nearly equal longitudinal 
areas ; in the anterior part of the body the muscles are very powerful, 
but posteriorly they become much thinner. The nervous system con- 
sists of a large brain, and a ventral nerve-cord which, alternately to 
right and left, gives off at right angles to the cord nerve-trunks which 
inclose ganglionic cells ; these nerves are inserted into the muscles, 
and extend over the lateral areas. Between the musculature and the 
internal organs there is a finely granulated layer, which is well de- 
veloped at either end of the body, where the cell-body is wanting. This 
body has an investing membrane within which are hyaline spheres ; 
these are feebly stained by borax-carmine, and are dissolved by xylol ; 
it must not, therefore, be called a fat-body. 
31ermis appears to form a link between Gordins and the Nematodes ; 
with the former it has in common the mode of life, the anuellation of 
the body in quite young larvse, the presence of a cell-body, and a ventral 
nerve-trunk. The generative organs of 31ermis, which have the form of 
a flat, broad band very rich in nuclei and placed asymmetrically on one 
side of the body, are quite similar to those of Nematodes. 
Sexual Elements of Ascaris of Dog.j — Herr S. M. Lukjanow has 
made a series of sections of the sexual tubes of the Ascaris of the Dog. 
* Arcli. f. Mikr. Anat., xxxiv. (1889) pp. 390-G (1 pL). 
t T. c., pp. 398-40S (2 pis.). 
