MOSS ANIMALCULES (BRYOZOA) 



955 



18 (16) Colony unbranched, gelatinous, with a flat "sole." 



Cristatella mucedo Cuvier 1798. 



External cuticula lacking, or developed merely as a thin gelatinous layer under the sole. 

 All polypides contract into a common cavity. Statoblast large, circular, with float and a cir- 

 clet of hooks on both sides. Young corm of circular form later elongated, worm-like, attaining 

 a length of 2 to 5 cm. in summer, to 28 cm. in autumn. Colonies often gregarious in a common 

 gelatinous substance. Eighty to ninety tentacles. Statoblasts with 10 to 34 dorsal hooks, 20 

 to 50 ventral hooks. Habitat, in standing or slow-flowing water, on submerged branches of 

 dead trees, under side of lily-pads, and on other aquatic plants. 



Statoblasts less than i mm. in diameter; hooks on dorsal side 10 to 22; on ventral side 



20 to 37 Var. a, genuina ( = C. ophidea Hyatt 1868). 



From Maine, Massachusetts, New York, Illinois, and Lake Erie. 

 Statoblasts over i mm.; hooks on dorsal side 20-34; on ventral side 38-50. 



Var. ft, idae ( = C. idae Leidy 1858; C. lacustris Potts 1884). 

 From Rhode Island and Pennsylvania. 



FIG. 1402. Cristatella mucedo. (a) Colony much enlarged. (6) Statoblast ventral aspect, (c) Statoblast 

 in pronle. X 25. (After AUman.) 



IMPORTANT REFERENCES ON FRESH-WATER BRYOZOA 



ALLMAN, J. 1856. A Monograph of the Fresh-water Polyzoa. London. 

 DAVENPORT, C. B. 1890. Cristatella: The Origin and Development of the 



Individual in the Colony. Bull. Mus. Comp. Zool., Harvard College, 20: 



101-152. 

 1891. Budding in Paludicella and other Bryozoa. Bull. Mus. Comp. 



Zool., Harvard College, 22: 1-114. 

 1904. Report on the Fresh-water Bryozoa of the United States. Proc. 



U. S. Nat. Mus., 27: 211-221. 

 HYATT, A. 1866-68. Obvervations on Polyzoa, Suborder Phylactolaemata. 



Communications Essex Institute, 4: 167-228; 5: 97-112, 145-160, 193- 



232. 



