MECZNIKOW, ON THE VORTICELLA-STEM. 285 
phrygia, describes an animal which, according to his descrip- 
tion, has little similarity with Lucernaria, and of which he 
himself remarks—‘“‘ De hujus genere etiamnum dubitans, 
pro tempore Lucernaris associavi, in multis tamen hydris 
affinem,” but which, nevertheless, has been included in many 
works under Lucernaria. Blainville, it is true, remarks that 
it cannot belong to the genus Lucernaria, but adding that it 
cannot even be placed under the type of his Actinozoa. He 
consequently makes of it a distinct genus, Candelabrum, 
which he places among the Sipunculide. 
Steenstrup, who, as has been stated, first made out from 
the manuscripts of O. Fabricius his LZ. auricula, has at last 
pointed out the true place of L. phrygia. According to him, 
it is a colony of hydroid polypes, most nearly resembling the 
genus Acaulis of Stimpson. 
RESEARCHES on the Nature of the VortTIcELiA-stEM. 
By Exias Meczntxow.* 
Tue question respecting the anatomical and chemical 
structure of the lowest organisms possesses at the present 
time a special interest from its relation to the discussions re- 
garding the cell-theory, which have of late been carried on 
so warmly. In order to throw some light upon this ques- 
tion, the author, under the guidance of Professor Sezelkow, 
undertook a series of researches respecting the behaviour of 
some of the Infusoria towards various physical and chemical 
reagents. ‘These researches, however, being incomplete, he 
has in the present paper confined himself to a portion of 
them to which he had devoted more particular attention, viz., 
on the stem of Vorticella. 
With regard to the nature of this organ, two principal 
views have been for a long time entertained. According to 
one of these, first enunciated by Ehrenberg,t the central 
streak in Vorticellais a muscle. Dujardin,{ on the other 
hand, denied the muscular nature of this part. Both views 
have found advocates. In favour of the former of them, we 
have Eckhardt, Czermak, Leydig, Claparéde, Lachmann, and 
Kiihne. Eckhardt§ confirms Ehrenberg’s view, and, more- 
* ¢ Archiv. Anat.,’ 1863, p. 180. 
+ ‘Die Infusionsthierchen,’ &e., 1838, pp. 274, 279. 
¢ ‘Hist. Nat. des Infusoires,’ 1841, pp. 49, 50, and 547. 
§ ‘Archiv f. Naturgeschicte, 1846, i, pp. 217, 218. 
