500 Miscellaneous. 



little drop of the fluid is spread upon a glass plate, a multitude of 

 small granules are perceived by the naked eye. These granules, or 

 rather capsules, measure from -p^th to T^jth of a millimetre. Under 

 a magnifying power of 300 to 400 diameters, an immense quantity of 

 filiform spermatozoids, regularly disposed from the centre to the 

 circumference, may be distinguished in their interior. By compressing 

 one of these capsules with a plate of thin glass, it is made to burst, 

 and then the spermatozoids escape, animated by movements which 

 leave no doubt as to their nature. 



The ordinary small vesicles in which the spermatozoids are formed 

 continue their development here by increasing considerably in size, and 

 thus become to a certain extent spermatophora. These corpuscles 

 are all found in the same state during a great part of the year, both 

 in the seminal receptacles of the females and in the testes and the 

 copulatory joints of the palpi of the males. At the period when the 

 eggs are to be fertilized, the spermatophorous capsules burst, and 

 then, the spermatozoids being set free, the seminal fluid presents its 

 ordinary aspect. Comptes Rendus, April 9, 1860, p. 727. 



Note on the Larva of a Nematode Worm, and on some remarkable 



peculiarities of the Generative Organs in the Nematoda. 



By A. SCHNEIDER. 



M. Schneider calls attention to a sort of alternation of generations in 

 a Nematode worm, which he calls Alloionema appendiculatum. In the 

 Black Slug (Arion ater) he found the larva of a Nematode worm, 

 possessing neither a mouth nor an anus, but simply the rudiments of 

 an intestinal canal and of generative organs. This larva is further 

 characterized by the existence of a curious appendage on each side 

 of the posterior part of the body. When these larvae are placed in 

 animal matter in a state of decomposition, they become developed, 

 acquire a mouth, and attain their sexual maturity. These animals 

 then propagate during a great number of generations, but without 

 passing again through the larval phase observed in the Arion. 



Another interesting discovery of M. Schneider's is that of a her- 

 maphrodite Nematode worm, the first with which we are acquainted. 

 He gives it the name of Pelodytes hermaphroditus. This animal 

 occurs in the larval state in Snails. When an individual is placed by 

 itself in a watch-glass with animal substances in a state of decompo- 

 sition, it soon attains its sexual maturity. Spermatozoids are first 

 seen to make their appearance in the generative tube, and then eggs ; 

 fecundation takes place, and a new generation is brought forth. To 

 those who know the perfect similarity which exists between the evo- 

 lution of ova and that of spermatozoids in the Nematoda, this fact, 

 notwithstanding the great interest attaching to it, cannot be sur- 

 prising. Siebold und Kolliker's Zeitschrift, 1859, p. 1/6. 



