Miscellaneous. 79 



greater doubts. One hundred scoleces of Ccenurus were given to a 

 young dog taken from its mother and carefully isolated. Twenty 

 days afterwards its intestine contained 237 Tcenice, the size of which 

 varied from 4 to 60 millimetres. Other experiments afforded abso- 

 lutely negative results. 



The authors also made experiments as to the production of the 

 Ccenurus in the Sheep by the administration of proglottides of Taenia 

 serrata. To each of two young sheep they administered ten seg- 

 ments of Tcenia serrata, all containing a number of perfectly mature 

 eggs, in which the embryo, furnished with its hooks, could be distin- 

 guished. These sheep never presented any of the phenomena of 

 staggers, which are stated to occur from the fifteenth to the twentieth 

 day after administration. Not to be in too great a hurry, they were 

 kept for four months. Then, although they appeared perfectly 

 healthy, they were killed in order to allow the examination of the 

 brains : no trace of Ccenurus could be detected. From this, and 

 considering the doubts arising when the assertions of experimentalists 

 are attentively examined, the authors do not hesitate to affirm that 

 the progeny of the Tcenia of the Dog never arrives at the brain of 

 the Sheep. 



Whilst denying the necessary transmission of the Entozoa as 

 described by most modern zoologists, the authors recur to the old 

 notion that the Cystic worms are produced from germs of Tcenice 

 which have found their way into places not fitted for them. — Comptes 

 Rendus, May 5, 1862, p. 958. 



On the Early Stages of Microdon mutabilis. 

 By M. Elditt. 



An enigmatical animal, which appears to be a Mollusk, and yet, 

 on closer examination, exhibits many characters foreign to the Mol- 

 lusca, and presents few points for comparison with other animals, 

 was known to some of the older zoologists, such as Aldrovandus, 

 but was first described and figured by Von Heyden in 1823. At 

 p. 1247 of the 'Isis' for that year is Von Heyden's memoir " Ueber 

 ein sonderbar gestaltetes Thierchen," which he found in 1818 at a 

 considerable elevation on the Hoche Mountain, under the moist bark 

 of an oak-stump standing near water. Only one example could be 

 found. Von Heyden thought that it was not a larva, but rather a 

 Mollusk which would prove a new and very remarkable genus. In 

 the following year Spix described, before the Academy of Sciences in 

 Munich, a new genus of terrestrial Mollusca to which he gave the 

 name of Scutelligera Amerlandia, because he found it at Amerland, 

 on the Stahrenberg Lake, in the interior of old rotten oak- and pine- 

 stumps still rooted in the ground, always in company with the Her- 

 cules and Red Ants ('Hesperus,' No. 295). In 1825, Von Heyden 

 called attention, in the ' Isis,' to the great resemblance between the 

 animals described by Spix and himself, but expresses his opinion 



