154 EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 



burgh in 1801, and by Dr. Lesauvage of Caen in 1818 (Bulletin de la 

 Facult^ de Medicine de Paris, torn, vi, p. 115). How is it, asks the 

 author, that this worm, found but twice in large quantity, has not been 

 met with more frequent, viz., near to Strasburgh in 1801, and on the 

 Island of Bornholm in 1841 ? It is this which* is very difficult to ex- 

 plain, especially by myself and others, who do not advocate spontaneous 

 generation. December, p. 355. 



Necrology. In the December number of the Annales for the year 

 1841, will be found the biography of the late JEAN VICTOR AUDOUIN, and 

 discourses on this much lamented and distinguished naturalist, by M.M. 

 Serres, Chevreul, Milne Edwards, and Blanchard ; to which is appended 

 a chronological list of the zoological writings of this respected observer. 



M. Edwards has also detected in the interior of Stephanomia prolifera, 

 with the assistance of a powerful microscope, an innumerable quantity 

 of very active white corpuscles of a pyriform shape, and terminating in 

 an extremely fine tail ; the movements were in every respect those of 

 spermatic animalcules, and it was impossible for him to consider them in 

 any other light than true zoosperms. He likewise describes ovoid cap- 

 sules, grouped near to the pyriform sacs, which he calls testicles, thereby 

 endeavouring to show that these singular animals are provided with male 

 organs. October, p. 228. 



Leon Dufour on the Metamorphoses of the Cecidomyia of the Sea Pine 

 and Poplar. An interesting paper to the Entomologist, with several 

 microscopic remarks. October, p. 257. 



Sars on the Development of Acalephce (Medusa aurita and Cyanea capil- 

 lata) . The following are the most important results arrived at by the 

 author connected with this class of animals : 1, Spherical eggs con- 

 tained in ovaries, on which may be observed the vesicle of Purkinje, the 

 spot (vesicule) of Wagner, and on which the jaune offers the division or 

 ordinary bifurcation, give birth to young of an oval or cylindrical- oval 

 form, furnished with vibratile cilia, contained during a certain period of 

 their development in numerous receptacles, which form at the same time 

 in the four arms surrounding the mouth of their parent. 2, Shortly, 

 these young quit their parent, and swim for a certain time similar to 

 Infusoria ; they then soon fix themselves by one of their extremities to 

 a foreign body, on which they grow, whilst at the other extremity they 

 are free ; a mouth is situated at the free end, and around this opening a 

 row of tentacles is formed. 3, In this polypoid state, w r hich may be 

 considered that of a larva, these animals are capable of propagating by 

 budding similar to Polyps, that is to say, by gemmae and stolons : new 

 animals produced by these means closely resemble the primitive larvae. 

 4, Lastly, after an indeterminate space of time, the larva divides spon- 



