ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1003 



■wanting ; its chief function is to contain and separate from the rest 

 of the parenchyma a more or less large part of the unpaired eflferent 

 canal ; this last, fi'om the nature of its walls, ought to be divided into 

 three, not two divisions. The uterus, near its cloacal end, is always 

 surrounded by a delicate layer of glandular cells, and its extremity 

 has the function of a seminal vesicle. The canal of Laurer is not a 

 vagina, and it may contain spermatozoa, yolk-globules, or even ova ; 

 it may be regarded as a kind of safety-duct which allows of the 

 passage to the exterior of a superabundance of genital products. The 

 only possible mode of fecundation is an external " autofecundation." 



The excretory system is disposed in similar manner in all the 

 members of the group. The spongy cords which have been the sub- 

 ject of so much discussion, are definitely regarded as being nerve- 

 fibres. The large multij^olar cells which are so abundant in some 

 parts of the body are evidently nervous in nature, and cannot by any 

 means be allowed to be gland-cells, or annexes of the vascular 

 system. 



M. Poirier discusses in a note* the recent observations of Dr. 

 Guffron, and expresses his belief that the German naturalist has 

 been a little hasty in his generalization that the nervous system of 

 Trematodes consists of six posterior longitudinal trunks ; in various 

 Distomes the lateral nerves appear to be wanting, and the dorsal 

 nerves only extend over the anterior half of the body; while the 

 dorsal and ventral nerves have a distinct origin in the cerebral 

 ganglia. 



Anatomy of Bilharzia hsematobia-t — Dr. G. Fritsch describes 

 briefly the structure of this parasite, which, as is well known, has 

 the male and female sexual organs in different individuals. 



The surface of the body of the female is beset with fine hairs ; 

 the alimentary canal commences with the mouth-sucker which leads 

 into the pharynx ; the intestine is narrow and soon divides into two 

 branches which afterwards reunite and terminate blindly. The 

 excretory apparatus opens through a large cavity at the hinder end 

 of the body ; from this arise two lateral and median trunks. With 

 regard to the generative organs, they are not widely different from 

 those of other Distoma. 



The male has a simpler structure on the whole than the female, 

 the alimentary canal is, however, identical in form with that of the 

 other sex. The sexual organs are extraordinarily simplified ; they 

 consist of about five testicular sacs which unite into a short vas 

 deferens provided with a vesicle ; there is no penis ; the male 

 generative aperture is in common with the excretory pore. 



Small Rod-like Cell-contents of certain Cercariae.f— Dr. P. 



Sonsino in investigating the histology of some Cercana-forms has 

 discovered a probable function for the cells containing small rod-like 

 structures (" cellules a batonnets "), which have been noted by several 



* Arch. Zool. Exp6r. ct Ceii., iii. (1885) pp. xxvii.-ix. 

 t Zw.l. Anzcif?., viii. (1885) pp. 407-11. 



♦ Arch. Ititl. clc liiul., vi. (IBHrj) pp. 57-(;i. 



