NO. 1355. FRESH-WATER BRYOZOA— DAVENPORT. 217 



without hook.s; cither free, elliptical, with broad tloat, or (in the hori- 

 zontal tubes) without tioat, oi" large size and irregular shape. 



The coninionest genus of our fresh-water Bryozoa. Has been 

 reported from all continents except Africa. Lives in the most diverse 

 habitats, in ponds or streams, usually not in the light. 



PLUMATELLA PRINCEPS Kraepelin. 



PlumateUa eniarglnata Allmax, 1S44. 

 Plumatclla repens van Beneden, 1848. 

 Plumntella diffusa Leidy, 1851. 



Branches both A'ertical and horizontid. Cuticuhi thick iuid t»i(»\vn 

 with a keel that broadens at the aperture. 



Var. ^»', cmcm/mata. — Tubes openly branched, repent, with short 

 lateral branches, antler-like. (Plate V, tig. 5.) 



* Squaw Bay, Put-in Bay, July 17 and IS, ISilH, on lily stems and 

 leaves; * Rondeau Harbor, Ontario. August 30, 1899; * Flathead 

 liiver, Montana Bavou, on bark and rotten logs, August 19, 1891 

 (Forbes); *Big Creek, Hamilton County, Illinois, October 3, 1900. . 



Var. ft^fi'tit!e<>f<'i.~Q,o\oi\\ robust, branched, often rising from sub- 

 stratum. Keel little developed. Statoblasts elongated. 



*Erie, Pennsylvania, Boat Landing, August 16, 1899. 



Var. y, mucosa. — Vertical branches predominate, forming an inter- 

 twined mass. 



Var. 8, spongiosa {— Alcyo7ieUa Benedenl Allman). — Vertical tubes 

 fused into a mass from wdiich only the apertures rise free. 



Havana, Illinois, Station G (Thompson's Lake), April 10. 1895; 

 Matanzas Lake, Blinois River, July 9, 189(1. 



PLUMATELLA POLYMORPHA Kraepelin. 



With vertical as w^ell as horizontal tips of branches. Cuticula r<ir<h/ 

 l)rowned or keeled. Includes numerous synonyms, especialh' Phiitta- 

 tdla covaUlo'xles Allman; P. elcgans Allman; ]\ diuiiortieri Allman; 

 P. nitida Leidy (1851); P. arethma Hyatt (1868). Found on all con- 

 tinents except Africa. 



Var, a^re2)ens {=P. arethum Hyatt). — Tubes creeping wnth short 

 vertical side branches. Cuticula mostly semitransparent; keel not 

 evident. (Plate V, fig. 6.) 



* Squaw Bay, Put-in Bay, July 12, 1899; *Long Point, Canada, 

 August 23,24, 1899; * Rondeau Harbor, Ontario, "East Swamp" and 

 Business Creek, August 28,29, 1899; *Swan Lake. Montana, under 

 stones, August 21, 1891; *Havana, Illinois, Station L (Dogfish Lake^. 

 August 7 and 23, 1895. 



This form varies greatly in the thickness and transparency of the 

 euticida. The specimens from Long Point have an unusually thick 

 and clear cuticula. 



