644 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



animalcules increase three- or fourfold 

 in twenty-four liours, and may thus pro- 

 duce a million from a single animalcule 

 in ten days. An abundant supply of food 

 favours self-division. In infusions and 

 amongst Oscillatorics, &c., in stagnant 

 marsh-waler. 1-240' ' to 1-96' '. 



S. jJi^stulata {Trichoda Acarus, M.; Ke- 

 rona ji^istulata, Duj.), — White, turbid, 

 elliptical or oval compressed, attenuated 

 at both ends, and ha^dng a band of im- 

 cini at the middle of the belly. Ehren- 

 berg has seen transverse and longitudinal 

 division, and the gro-wiih of gemmae. In 

 infusions and stagnant marsh-water. 

 1-144". This species has been seen in the 

 encysted state by Stein and Schneider 

 (xxix. 18). The white colour is no cha- 

 racteristic, since it is frequently green 

 from food received. Schneider {A. N. H. 

 2 ser. xiv. p. 328) observes that after 

 exclusion from their cysts they present 

 a remarkable resemblance to Oxytricha 

 caudata -, the posterior extremity in par- 

 ticidar is always bent round in the man- 

 ner represented by Ehrenberg. Pineau 

 calls this animalcule, in his history of a 

 transformation of Vorticella, by mistake 

 an Oxytricha (see Ann. d. Sc. Nat. 1848, 

 ix.). Cienkowsky, Jiowever, regards both 

 this species and &f. lanceolata as phases of 

 existence of the same being as Oxytricha 

 Pellionella and O. gihha. I 



S. Silur us (^Trichoda Silurm, Kerona Si- j 



liin/s, M., I)uj ., and Pert}-). — Small, white, 

 of the fonn of a mussel ; cilia and uncini 

 rather long. In fi'esh water. 1-280". 



S. appendiculata. — Elliptical, white, 

 small, and flat ; cilia and styles long ; the 

 setae disposed obliquely in fascicles. In 

 fresh water. 1-280". 



S. Histrio (^Paramecium Histrio, Ke- 

 rona Histi'io, M. and Perty). — Elliptical, 

 white; middle slightly turgid, termi- 

 nated anteriorly by a cluster of uncini ; 

 no setfe. Ehrenberg states that the ab- 

 sence of the three posterior setae in this 

 and the following species is remarkable, 

 inasmuch as the others possess them. 

 Fission transverse. Amongst Confervas. 

 Dujardin is inclined to regard this as a 

 mere variety of S. {Kerona) jJustulata. 



S. lanceolata. ( = Kerona lanceolata, 

 Duj. and Perty) (xxv. 343, 344).— Pale 

 greenish ; lanceolate in shape, extremities 

 equally obtuse, under side flat ; it has a 

 cluster of micini near the mouth, but no 

 styles. Ehrenberg saw in one specimen 

 a simple contractile vesicle on the left 

 side, below the mouth, and near it a 

 large oval gland. Green Monads and 

 Bacillaria may be seen in this voracious 

 animal, surroimded with colourless sto- 

 mach-juice, (xxv. 343 represents an 

 under view, and 344 a side view.) 

 Amongst Confervae. 1-144" to 1-120". 

 (See note on St. pustulata.) Encysted 

 state observed (xxviii. 74-76). 



Genus HALTERIA (Duj.) (XXYI. 31).— Body nearly globular or turbi- 

 nate, surrounded by long, very fine, retractile cilia, which adhere to the glass, 

 and by their sudden contraction enable the animal to change its place briskly, 

 as if by leaping ; a row of very strong oblique cilia occupies the circum- 

 ference. 



The type of this genus is Halieria Granclinella (XXYI. 31 a, h, c), called 

 by Ehrenberg TricJioclina, and placed by him in the family Yorticellina, 

 along with species totally different. Dujardin, however, more correctly 

 refers them to the family called Keronina (see p. 640). 



Genus MITOPHORA (Perty) (XXYIII. 46, 47).— Body small, thicker 

 behind, having on one side a row of large cilia, and posteriorly a filament of 

 nearly the length of the body, and either with a simple or a slightly nodose 

 extremity. 



MiTOPHORA dubia (xxviii. 46, 47). — , the other. Movement sluggish, revolv- 

 Hyaline ; sometimes filled with green j ing. It has some resemblance to Tri- 

 corpuscles ; with the characteristic row i choda prceceps (M.). 1-450". 

 of larger cilia along one side, and few on I 



Genus STICHOTRICHA (XXYII. 43, 44).— Lancet-shaped, cylindi'ical, 

 elongated anteriorly and flat ; mouth at this portion ; on one side an oblique 

 row of cilia. 



Stichotricha secitnda (xxviii. 43, | molecules or chlorophyll-grains ; cylin- 

 44). — Hyaline ; usually filled with grey i drical or rather compressed, rounded or 



