GENUS EPISTYLIS. 701 



Epistylis galea, Ehr. Pl. XXXIX. Fig. 6. 



Bodies elongate-conical, about three times as long as broad, attenuate 

 posteriorly, the frontal margin dilated ; cuticular surface smooth and plastic, 

 exhibiting transverse folds posteriorly when contracted ; vestibular entrance 

 prominent, projecting laterally in a spout-like manner ; zoodendrium rela- 

 tively short, thick, profusely and dichotomously branched ; secondary 

 branches not exceeding the zooids in length, articulate at each bifurcation. 

 Length of bodies 1-120"; height of entire colony 1-24". 



Hab. — Fresh water, on Ceratophylhim and other water-plants. 



In its general mode of growth the branching pedicle of this species accords most 

 nearly with that of Epistylis digitalis, but is readily distinguished from that type by 

 its simply articulate ornamentation ; the contour of the supported zooids at the same 

 time somewhat resembles that of Epistylis pUcatilis, a similar transverse plication of 

 the posterior region of the body being furthermore exhibited during contraction. 



Epistylis anastatica, Linn. sp. Pl. XXXVIII. Figs. 19-22. 



Bodies in extension conical-campanulate, nearly three times as lono" 

 as broad, attenuate posteriorly, the frontal margin dilated, spheroidal or 

 ovate, with a snout-like projection when contracted ; cuticular surface 

 smooth, or finely striate transversely ; the ciliary disc raised above the 

 border of the peristome in a tongue-like form ; pedicle moderately thick, 

 entirely smooth, neither striate nor articulate, often squamose through 

 the adherence of other minute parasitic forms, branching profusely and 

 dichotomously, secondary branches attenuate, equal to or exceedino- the 

 length of the zooids. Length of bodies 1-280" ; height of entire colony 

 I-15". Hab. — Fresh water, on Entomostraca and aquatic plants. 



The entirely smooth pedicle and more attenuate character of the secondary 

 branches, as well as the considerably smaller size of the zooids, distinguishes this 

 species from the preceding ; this same character of the pedicle, added to the greater 

 dilation bf the peristome-border, separates it also from E. digitalis, in whose com- 

 pany it not unfrequently occurs. In examples recently examined the author has 

 detected the presence of fine transverse strife upon the cuticular surface, though 

 these are not so conspicuous as to be generally observable. Ehrenberg remarks that 

 the branching pedicle of the colonies found growing on water-plants is usually more 

 attenuate than when attached to Cyclops qiiadricornis or other animal hosts. By 

 Linnaeus,* as also by O. F. Miiller, this species is described under the title of Vorti- 

 cella anastatica. 



Epistylis plicatilis, Ehr. 

 Pl. XXXVIII. Figs. 6-8, and Pl. XXXIX. Figs. 12-15. 



Bodies elongate-conical, attenuate posteriorly, three or four times as long 

 as broad ; cuticular surface soft and flexible, plicate, or exhibiting several 

 annular folds posteriorly when contracted ; the frontal margin dilated ; the 

 ciliary disc much elevated ; pedicle slender, finely striate longitudinally, 

 profusely and dichotomously branched, often corymbose, the secondary 



* 'Systema Naturre,' Ed. xii., 1767. 



