596 



SYSTEMATIC HISTORY OF THE INFUSOEIA. 



Z. dichotoDiiim. — Stem very regularly 

 dichotomous; pedicles long; zooids cylin- 



drical, resembling fruit of the Rosa eanina. 

 7a. plumosum (Wright) =Z. niveum. 



Genus SCYPHIDIA (Duj.). — Sessile, cup-shaped, tapering at the base, 

 covered with a reticulated integument. 



This genus is received both by Perty and Lachmann. The former notices 

 three species, of which one, ^dz. Sc.patida, is new, the two others being 8c. 

 rlngois and Sc. pyriformis. Lachmann, on the contraiy, although admitting 

 the genus, rejects the species of Dujardin and Perty, '' as they have a short 

 stem, and appear to be only particular states of pedunculate Vorticellina, in 

 which the stem has not attained its usual length ; but on the other hand," he 

 continues, '' two other beings must be referred to it, both of which attach 

 themselves to the naked parts of small freshwater mollusca, and never form 

 a stem, but which were often observed by me in process of division, and are 

 easily distinguished from other forms which are, like them, attached at first, 

 by their posteriorly- truncated form, and a projecting pad at the margin of 

 the hinder end." 



ScYPHZDiA rugosa. — Obloug, marked 

 with distant oblique deep striae, looking 

 like furrows. 1-565". In pond-water, 

 amongst vegetable debris. To this genus 

 Dujardin would also attach the VoriiceUa 

 ringens and V. mcUnans of Miiller, and 

 possibly also the V. pi/rifoi'mis of the 

 same author, under which name Ehren- 

 berg has described a variety of V. conval- 

 laria. 



Sc. pynfonnis. — Grey, hyaline ; with 

 no pedicle, or an extremely short one ; 

 constantly contracting itself. Uncom- 

 mon ; on Cyclops, &c. Length, in- 

 cluding stem, 1-720" to 1-600". Is 

 closely allied to Sc. ringens. 



Sc . patida (Perty) . — Widely campanu- 

 late ; of a bluish-grey colour ; stem half 

 the length of the body. Length, with 

 stem, 1-360". Uncommon, with Tota- 

 mogcton. 



Votiicella hamata (Ehr.) is probably 

 another species, and identical with V. in- 

 clinans, which Dujardin numbers among 

 the Scyphidia. 



Sc. limacma (Lachmann) = Vorticella 

 limacina (Miill.) (xxix. 3). — Body nearly 

 cylindrical, tapering a little at each end, 

 and annulated ; periston! narrow and not 

 turned backwards ; ciliary disc naiTow, 

 and furnished with a projecting umbi- 

 licus in the middle ; the posterior trun- 

 cated smface provided with a thick pad- 

 like margin. ^ 1-240" to 1-360". Lives 

 on small species of Planorhis. 



Sc. Physannn (Lachmann) is longer 

 and more uniformly cylindrical than the 

 preceding, the periston! longer ai!d often 

 tiu*i!ed backwards (everted), and the 

 hinder margin thinner and shoi'ter. 

 Lives on the naked parts of species of 

 Physa. 



Genus UECEOLARIA (Lamark and Duj.). — Body not ciliated throughout, 

 contractile, varjing in shape from hemispherical or discoid to globular ; sui'- 

 rounded by a plane margin fringed Avith a row 'of strong ciHa planted 

 obliquely, which makes a spiral turn inwards at the oral apertiu'e, which is 

 also situated on the margin. 



Vorticellina of different kinds have been mistaken for examples of this 

 genus, and Ehrenberg has placed some of its members among the Trichodince ; 

 indeed the type of Urceolaria is the Trkliodina Pedicidiis of Ehrenberg. 



Many species of this genus are parasitic on freshwater Mollusca and Zoo- 

 phytes ; but Miiller mentions some found by him in sea-water. 



There appear no sufficient grounds for instituting this genus when that 

 of Trichodina is admitted, as it is by naturalists generally. • 



Vb.C'EOI.xtlix stellma=TncJwdiiui Pe- \t\\Q border of the disc ciliated. In 

 dicidus (Ehr.). \ sea-water. Uncommon. Ehrenberg has 



U. discwa= Vorticella discina QsL). — j treated this form as identical with Tri- 

 Described by Miiller as orbicidar, hoi- | cAof7/;mP^r7?W//?^<?, but, as Dujardin thinks, 

 lowed out alDove, convex beneath . . . ; erronooiisly. However, it is impossible 



