SPECIES OF STENTOR 337 



S. rubra Bary 1950. A small, pink stentor like igneus but 

 distinguished by a rim-like margin on the frontal disc exterior to 

 the membranellar band. (One wonders if this is merely a variety 

 of igneus.) 



The following species have no pigmented granules and appear 

 white by reflected light, except when containing symbiotic 

 chlorellae : 



S. polymorphus (Miiller, 1773) Ehrenberg. A large (250 /a) not 

 self-pigmented stentor without a case, usually grass-green with 

 symbiotic Chlorella. (My observations confirm Johnson's, that 

 this species is probably never entirely free of chlorellae unless 

 special steps were taken to remove them.) 



S. roeseli Ehrenberg 1835. This is a small (140/x) colorless 

 stentor which lives in a case. Usually, but not always, the posterior 

 nodes of the moniliform macronucleus run together as a rod, or 

 are more spindle-shaped than the anterior nodes. (In both this and 

 the following species — muelleri — the stretched animal shows a 

 much attenuated stalk right up to the well-expanded frontal disc, 

 hence the shape of an uncoiled trombone; and both show con- 

 spicuous "bristles" or quiet and extended lateral body cilia near 

 the anterior end.) 



S. muelleri (Bory St. Vincent, 1824) Ehrenberg 1838. A medium- 

 sized (250 /Lt) stentor without pigment granules which produces a 

 thick lorica. The cytoplasm is rather brownish in color. The frontal 

 field generally rests at an angle to the cell axis, hence cala-like in 

 shape. With uniform chain macronucleus. 



A stentor with dark pigment of undetermined color because 

 described only from preserved specimens : 



S. pygmceus Swarczewsky 1929. A medium-sized pigmented 

 stentor with an abbreviated, chitinoid case found attached to 

 certain Crustacea (gamarids) in the deeps of the Baikal Sea. 

 (Apparently the case is used chiefl)^ for attachment because most 

 of the animal does not withdraw into it. There is a short, monili- 

 form macronucleus with 4 to 6 nodes.) 



This list includes species recognized by Kahl, as well as the new 

 species loricatUy rubra^ Felicia and introversuSy described since his 



