1888.] MICEOSCOPICAL JOURNAL. 101 



process on each side ; axis a cylindrical cord ; polyp bell-shaped, mouth 

 oblique, tentacles 12-16. Habitat, running water. U. gracilis., Leidy. 

 Fig. I. • 



3. Plumatella. 



I. Colonies filiform, branching, prostrate or tufted; tentacles 40 to 50; 

 cells subclavate, triangular or subcylindrical in transverse section. P. repens, 

 Leidy. Fig. 3. 



3. Colonies prostrate and branched, or erect and dendroid ; cells tubular, 

 increasing in diameter toward the free end, always triangular in transverse 

 section. P. hicifiiga., Vaucher. Figs. 3, 6, 7. (Dr. Jullien identifies 

 Fredericella sufiana ^vith this.) 



3. Cells distinct, brov^^n, tough ; branches adherent or not, often colorless ; 

 colonies dense or diffuse ; tentacles 40 to 60. P. aretlmsa., Hyatt. Fig. 4, 

 life size. (Dr. Jullien doubtfully identifies Fredericella regitta with this.) 



4. Colonies prostrate and adherent only ; ends of the branches yellowish 

 or hvaline ; cells inxeolate near the deeplv emarginate orifice ; tentacles 43 ; 

 lophophore reniform. P. diffusa^ Leidv. Fig. £5, natural size. (Dr. Jul- 

 lien doubtfully identifies Fredericella li^alcollii with this.) 



V Cells striate longitudinally, the extremity annulate. P. lineata., Pai^fitt. 

 6. Cells spatulate, prostrate, entirely adherent, orifice in the centre of the 

 enlargement. P. limnas., Parfitt. 



(Dr. Jullien identifies Nos. 5 and 6 with P. repens.) 



3. Fredericella. 



Lophophore oval ; colonies attached, dendritic ; cells elongated. (This, 

 according to Jullien, is a variety of Plumatella, or rather an arrested devel- 

 opment of the latter.) For the following the writer is indebted to Hyatt's 

 ' Polyzoa :' — 



I. Main branches closely adherent, forming long single stems, often cross- 

 ing, the angles acute, the free cells or branches rising abruptlv ; colonies 

 covering large areas. F. Walcotlii, H)att. 



3. Branches colorless, usually entirely adherent, the free parts of the cells 

 occasionally branching ; colonies radiating. F. pidc/ierritJia., Hyatt. 



3. Colonies very variable in form, tentacles iS to 33. Var. a. Colonies 

 not large, branches numerous ; attached parts of the cells very long, the free 

 portions mere nubs on the branches. Var. b. Main branches not necessarily 

 adherent, but growing in clumps, the colony often attached only by a part of 

 a branch, the free portions of the cells long, on wide surfaces. Var. c. Growth 

 dense, branches crowded, sometimes adherent ; found only on limited sur- 

 faces of small twigs ; colonies sometimes i to 3 inches deep by 3 to 4 long. 

 F. regina., Leidy. Figs. 8, 9. 



4. Hyalinella. 



1. Colonies colorless hyaline, or brown transparent, radiating, branching, 

 prostrate, the branches not adherent ; cells about j^^ inch long and wide, 

 slightly dilated. H. vesicularis (Leidy), Jullien. Fig. 10, natural size. 

 (Dr. Jullien thinks this and Leidy's Plumatella vesicularis are the same ; 

 he also doubtfully identifies Fredericella fulcherriina with this.) 



2. Colonies radiating or linear, the thick, colorless gelatinoid cells more or 

 less projecting. H. vitrea (Hyatt) , Jullien. Fig. 11, natural size. (Dr. 

 Jullien thinks this is Hyatt's Plumatella vitrea.) 



5. Lophopus. 

 Colonies -^-^ to \ inch in diameter, usually branched ; tentacles 40 to 50. 

 L. Trembleyi., Jullien. (This has not yet been found in the United States.) 

 Fig. 13, natural size, attached to rootlets oi Lemna. 



