STENTOR. 



[ 736 ] 



STEPHANOSPH^ERA. 



line resembling a rib, up the centre of each 

 fertile lobe. Tetraspores and antheridia 

 unknown. 



BIBL. Harvey, Marine Alg. 123, pi. 15 D. 



STENTOR, Oken. A genus of Hetero- 

 trichous Infusoria, of the family Bursarina. 



Char, Body conical or trumpet-shaped, 

 free, or sessile and attached by the narrow 

 base, covered with cilia; anterior portion 

 widened and fringed with a marginal row 

 of longer cilia, with a spiral row of cilia 

 extending from it to the mouth. Fresh- 

 water. 



These Infusoria are among the largest 

 and the most beautiful of the class. The 

 body is very contractile and liable to varia- 

 tion in form, often becoming ovate, oblong, 

 or globular; the nucleus is moniliform or 

 strap-shaped. Reproduction by oblique fis- 

 sion, and by germs arising from the nucleus. 

 The encysting process has been noticed in 

 some of the species. 



According to Lachmann, in S. Mullen, 

 polymorphus, and Itceselii, near the plane of 

 the ciliary disk is a large contractile vesicle, 

 from which a longitudinal vessel with 

 several dilatations runs to the posterior ex- 

 tremity of the body"; also an annular vessel 

 round the ciliary disk, close under its row 

 of cilia. 



S. Mutteri (PI. 32. fig. 3). Body colour- 

 less unless from containing foreign coloured 

 particles, with a fringe of cilia or a ciliated 

 crest extending from the mouth to near the 

 middle of the body; nucleus moniliform. 

 Length 1-24" 



Several other species. 



Dujardin places this genus in the family 

 Urceolarina. 



BIBL. Ehr. Inf. 261 ; Stein, Infus., pas- 

 sim; Pritchard, Inf. 581; Clap.'et Lach. 

 Inf. 222; Kent, Inf. 588; Lankester, Qu. 

 M. J. 1873 (col. matter}. 



STEPHANOC'EROS, Ehr. A genus of 

 Rotatoria, of the family Flosculariaea. 



Char. Eyes single ; rotatory organ divided 

 into five tentacle-like lobes, furnished with 

 whorls of vibratile cilia; body attached 

 by the base to a cylindrical hyaline ca- 

 rapace. 



8. Eichhornii (PL 44. fig. 25). The only 

 species. Freshwater ; length 1-36". This 

 beautiful animal uses the lobes of the ro- 

 tating organ to catch its prey, in the manner 

 of Hydra. At a (fig. 25) are seen the tre- 

 mulous bodies, above which is a row of 

 roundish globules, called by Ehrenberg ner- 

 vous ganglia. 



BIBL. Ehr. Inf. 400; Pritchard, Inf. 

 668 ; Cubitt, Mn. Mic. Jn. iii. 240. 



STEPHANODIS'CUS, Ehr. A genus 

 of Diatomaceae. 



Char. Frustules discoidal, single ; valves 

 circular, alike, not areolar (under ordinary 

 illumination), and with a fringe of minute 

 marginal teeth ; freshwater. 



S. berolinensis has the valves finely ra- 

 diate, with mostly thirty-two teeth, and is 

 1-1150" in diameter. S. Niagara (PI. 18. 

 fig. 26) ; 8. lineatm (fig. 27) ; S. sinensis 

 (tig. 28) ; S. JEgyptiacus (fig. 29) ; S. Bra- 

 maputrce (fig. 29*). 



BIBL. Ehrenb. Ber. Berl Ak. 1845, Ixxii. ; 

 Kiitz, Sp. Alg. 21 ; Rabenht. Alg. i. 36. 



STEPHANOGO'NIA, Ehr. An obscure 

 genus of fossil Diatomaceae. 



Char. Frustules resembling those of Mas- 

 togonia, but with the apices of the valves 

 truncate, angular, and spinous. 



Two species found in Bermuda and North 

 America. S. polygona (PI. 18. fig. 30). 



BIBL. Ehrenb. Ber. Berl. Ak. 1844, 264; 

 Kiitz. Sp. Alg. 26; Pritch. Inf. 814. 



STEPHANO'M A = PANDOBINA. 



STEPHANOM'ONAS, K. A genus of 

 Cilio-Flagellate Infusoria. Free, ovate, 

 with an anterior circle of cilia, and a single 

 flagellum. S. locellus; freshwater. (Kent, 

 Inf. 466.) 



STEPH'ANOPS, Ehr. A genus of Ro- 

 tatoria, of the family Euchlanidota. 



CJiar. Eyes two, frontal, foot forked; 

 carapace depressed or prismatic; anterior 

 part of body expanded so as to form a fron- 

 tal hood ; jaws each with a single tooth. 



8. cirratus (PL 44. fig. 28). Carapace 

 with two posterior spines j freshwater ; 

 length 1-240". 



of. muticus has the carapace without spines 

 posteriorly, and the eyes have not been 

 recognized ; whilst S. lamellatus has three 

 posterior spines. 



BIBL. Ehr. Inf. 478 ; Pritch. Inf. 699. 



STEPHANOPYX'IS, Ehr. A genus of 

 Diatomaceae = Pyxidicula in part. 



STEPHANOSI'RA, Ehr. A genus of 

 Diatomaceae. 



Char. Frustules united into a short fila- 

 ment, disk with radiating series of minute 

 pun eta and a marginal crown of teeth. 

 Allied to Stephanodiscus and Melosira. On 

 trees. (Pritchard, Infus. 823.) 



STEPHANOSPELE'RA, Cohn. A ge- 

 nus of Volvocineae (Confervoid Algae). 

 S. pluvialis (PL 48. fig. 22) is nearly related 

 to Pandonna t consisting of a large hyaline 



