INVEKTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 575 



dinal canals, which run parallel to and above the arms of the cntcron ; 

 the primary trunks give off a largo number of small canals, which 

 extend into the parenchyma and seem to traverse every sjiace in it. 

 There are two large testes, a seminal duct with a vesicle, and a well- 

 developed cirrus (penis) ; the female organs are composed of an ovary, 

 an efferent duct, receptaculum seminis, vagina, utenxs, paired yolk- 

 glands and their ducts. This form seems to be distinguished from 

 all other Polystoinece by possessing three ducts carrying the deuto- 

 plasm into the oviduct ; the ovum seems to be matured as in other 

 Trematoda, but only one comes to development at a time. 



The genus Microcotyle was established by Van Beneden and Hesse, 

 but its . points of difference from Axine have never yet been very 

 clearly put out ; its most striking variation is now shown to lie in the 

 fact that, unlike Axine, it is completely symmetrical ; it is also dis- 

 tinguished by the absence of the penis, and the position of the vaginal 

 orifice in the median dorsal line of the body (in Axine this orifice is 

 marginal in position) ; while, again, Microcotyle does not present 

 merely one mature egg in its oviduct, but a number, which may 

 come to be as high as twenty-four. 



The new species, M. mormyri, is described by Herr Lorenz : Van 

 Beneden and Hesse had described four species, M. labracis from 

 Lahrax lupus, 31. Donavani from L. Donavani, M, erythrini from Pa- 

 gellus erythrinus, and M. canthari from Cantharus griseus ; as to the first 

 two the author is certain that his species from Pagellus mormyrus is 

 quite distinct ; as to the third species, the difficulties as to their proper 

 identity are removed not only by the difference in the arrangement of 

 the bands on the body, but by the more important character of the 

 bundles of chitinous rods, which are found aroimd the genital orifice ; 

 in 31. erythrini they are arranged in two small groups set one in front of 

 the other, but in 31. mormyri there are two sets; 8 to 12 are arranged 

 radially and in a curved manner, and behind and on either side there 

 are 25 to 30, which have their hooks directed forwards ; the points of 

 difference to 31. labracis are brought out in the full description of the 

 new form; in many points of its internal structure it is shown to 

 agree with Axine ; but the vagina forms a large vesicle, placed in the 

 middle of the body and provided with a wide orifice ; its superior 

 portion and margin have an almost chitinous character, but the lower 

 part has its wall thin, and is continued into a canal which is formed 

 by the union of the branches of the paired vitelline duct. The 

 coverings of the egg are proportionately very large ; they are of an 

 elongated oval form, and pass into a gradually diminishing appendage, 

 which is coiled at its tip ; in which character it also differs from 

 31. canthari, as described by the Belgian zoologist. 



Life-history of the Tape-worm of the Shrew.* -M. Villot an- 

 nounces the discovery of the cystic forms of two of the four species of 

 Tcenia which infest the European Shrews, and which have hitherto only 

 been known in the sexual stage. 



The two species of bladder worm are placed by Villot in a new 



* ' Auu. Sci. Nat. (Zool.),' viii. (1870) No. 2-3. 



2 Q 2 



