632 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Morphology of Vorticellinae and allied Ciliata.* — Prof. O. 

 Butschli discusses the problem of the process of division in the Vor- 

 ticellina), which appears to differ so much from what is found in allied 

 Ciliata ; it being, as we know, longitudinal instead of transverse, as 

 it is in most other forms. The suggestion arises that the difference 

 is not real, but is dependent on an incorrect morphological orientation 

 of the Vorticellino body. By the Vorticellina} the author means 

 the groups which Stein called Vorticellina, Ophrydina, and Urceo- 

 larina; they agree with all other ciliates (except the so-called 

 Holotricha) in having an adoral zone of stronger cilia, which, as 

 a rule, follows this course — the mouth is at some distance from the 

 anterior end of the body, is on the aspect which is called ventral, 

 and is frequently somewhat nearer to the left than the right side. 

 From it the zone extends to the left margin of a so-called peri- 

 stomial area, which generally corresponds to the left margin of the 

 ventral side, as far as the anterior end ; if it is well developed, as is 

 generally the case, it bends round to the right, and extends along 

 the right side of the ventral surface, more or less far back. The zone 

 takes a more or less well-marked spiral course which is especially 

 well seen in some Heterotricha (Stentor and others). This adoral 

 spiral in the Vorticellina has considerable resemblance to that of a 

 Stentor, but is especially distinguished by the fact that it appears 

 to coil to the right and not to the left. 



As to the origin of the Vorticellina, Prof. Butschli thinks it un- 

 necessary to take into consideration the restriction of cilia to the 

 ciliated zone, as he believes that this character has been acquired 

 within the limits of the group. On the other hand, it is quite clear 

 that the fixed have been derived from free-swimming forms. The 

 most primitive forms appear to be the Urceolarina, which have a 

 relatively simple peristomial structure, find among them the genus 

 Licnojihora ; the surface of its attaching disc is in a plane with the 

 peristome ; the hinder half of the body appears as a kind of stalk for 

 the disc. It seems to Prof. Butschli that this form can without 

 difficulty be derived from the other Ciliata, whether hypo- or hetero- 

 trichous. From an ectoparasitic infusorian, provided with a mouth- 

 spiral, which moves about by its ventral surface on the integument 

 of the animal on which it dwells, Licnopliora may be derived by sup- 

 posing that the ciliation became specialized into the ciliated circlet. 

 The hinder part of the ventral surface gradually developed into a 

 special disc of attachment, whereby the anterior part of the body, 

 with the spiral and the mouth, became emancipated from their inferior 

 position ; the mode of life of Kerona polyporum shows that this is not 

 a fanciful sketch. 



If the author's views are correct, the so-called ciliated organ of 

 the Vorticellinae must be regarded as the dorsal side, and all the rest 

 of the body as ventral ; in this case the point from which the stalk 

 of the fixed forms arises must be regarded as the middle point of 

 the ventral surface. With this new orientation we are able to explain 



* Moi'phul. Jabrb., xi. (ISSO) j>i>. 50U-65. 



