GENUS VORTICELLA, 687 



described by Leeuwenhoek in the 'Philosophical Transactions,' London, 1675, ^i^d 

 which subsequently {ib. 1703) received from him the more distinctive title of Bell-like 

 animals. Linnsus, in his 'Systema Naturae,' 1758, embodies the same species under 

 the name of Hydra convallaria, conferring upon it its generic title of Vorticella in 

 ed. xii. of the same work published in the year 1767. By some authorities this 

 species has been supposed to be synonymous with Ehrenberg's Vorticella micro stomum. 

 The dilated form of the frontal border in the present instance, however, as com- 

 pared with the constricted contour of this region in the last-named species, precludes 

 the serious entertainment of such a proposed identification. 



Vorticella hamata, Ehr. 

 Pl. XXXIV. Fig. 27, and Pl. XLIX. Fig. 35. 



Body elongate-conical, somewhat gibbous, about twice as long as broad, 

 constricted beneath the peristome-border and tapering towards the posterior 

 extremity, obliquely set upon its pedicle, evenly and elongate pyriforni 

 when contracted ; cuticular surface finely striate transversely ; pedicle 

 short, rarely exceeding twice the length of the body, usually less. Length 

 1-600". Hab. — Fresh water ; solitary or in small social groups. 



This species, as figured and briefly described by Ehrenberg, would appear to 

 accord more nearly with the Vorticella iticlinans of O. F. Miiller than the so-called 

 V. hamata of that authority, which is apparently a free-swimming type allied to Strom- 

 bidium. A form entirely agreeing with the Ehrenbergian species, as here figured and 

 characterized in the foregoing diagnosis, has been met with on various occasions 

 by the present author, and notably in company with Vorticella alba attached to 

 Chara and confervoid growths obtained from an aquarium of some years' stand- 

 ing in the South Kensington Biological Laboratory, during the months of January 

 and February 1880. The contour of this animalcule, with its rigidly extended 

 pedicle and obliquely set, gibbously ovate body, corresponds in a remarkable manner 

 with the spore-receptacle, theca or sporangium, of a Hypmun or other moss form. 



Vorticella spectabilis, S. K. 

 Pl. XXXIV. Fig. 35, and Pl. XLIX. Fig. 36. 



Body plastic and somewhat variable in form, elongate-conical, widest 

 anteriorly, tapering posteriorly, nearly three times as long as broad when 

 fully extended, subspheroidal in its contracted state ; the peristome dilated 

 and widely everted ; cuticular surface finely striate transversely ; parenchyma 

 coarsely granulate, lightish brown ; pedicle short and stout, rarely exceeding 

 two or three times the length of the body, more usually of the same length 

 or even shorter. Length i-i 50". Hab. — Pond water ; social. 



This species has been obtained by the author on one occasion only, being 

 then found, in June 1879, attached in social clusters to the leaves of duckweed, 

 Lemna minor, taken from a roadside pond near Ashby-de-la-Zouch. While most 

 closely approaching Vorticella campanula in the large size of the individual zooids, 

 it is readily distinguished from that type by the more attenuate contour of the 

 body, by its simple spheroidal and unpuckered outline in the contracted state, and 

 by the very short comparative length of the pedicle. A distinctive character con- 

 nected with this last-named element, that is well shown in permanently preserved 

 examples, is afforded by the fact that in the majority of instances the central 

 muscle-like fibrilla is not developed throughout the length of the pedicle, but from 

 its junction with the animalcule's body to a point midway only between this and its 



