95 COHN, ON NASSULA ELEGANS. 
incrusting material is phosphate of lime. The concentrically 
laminated corpuscles of Distoma nodulosum are soluble in 
acids without effervescence; the solution, on the other hand, 
being preceded by a swelling up of the substance, so that the 
presence in them of phosphate of lime can hardly be supposed ; 
the swelling being due solely to the organic basis. It has 
already been remarked by Ktichenmeister, that the so-termed 
calcareous corpuscles in Tenia solium, and denticulatum, 
Bothriocephalus latus, punctatus, and claviceps, dissolve in 
acids without effervescence. From this it is evident how 
insufficiently the true nature of these corpuscles in the 
‘Trematoda and Cestoda has been investigated. It is a point, 
however, well worthy of investigation, since the accurate 
knowledge of the chemical conditions of these bodies is cal- 
‘culated to throw a clearer light than we yet possess upon the 
function of the excretory system. 
[M. Claparéde’s paper, besides his observations upon the 
**Calcareous corpuscles,” contaims some upon the relations of 
the animal found in the Trematode-cysts from the Stone- 
Perch, ‘and which is regarded by him as belonging to the 
genus Tetracotyle of Filippi—to the Distomata and Cestoid 
worms. He expresses the opinion, that Tetracotyle, like 
Diplostomum, represents a division of an immature Trematode, 
and that it appears very probable that the corresponding 
mature forms are to be sought among the Holostomata.] 
On the Repropuction of Nassuta Evecans (Ehr.) By Dr. 
Frerpinanp Coun, of Breslaw. 
(Siebold and Kolliker’s * Zeitsch. f. w. Zool.,’ vol. ix, p. 143.) 
AxutuoucH the reproduction of the Infusoria by a motile 
internal progeny (schwiarmsprésslinge) is well established 
m the case of several species, the number of forms in 
which the production of endogenous embryos has been 
observed is so limited, that we are not at present justified in 
expressing a decided opinion as to the universality of this 
mode of reproduction, and it remains therefore a matter of 
interest still to collect new facts respecting it. In the course 
