522 ORDER HOLOTRICHA. 



examined it was observed that the animalcules possessed the capacity of extend- 

 ing to a much greater length than is indicated in Quennerstedt's drawings, which 

 must be accepted as a comparatively contracted state ; the new figure, PI. XXVII. 

 Fig. 40, as here given, more correctly illustrating its typical and fully extended con- 

 dition. The elasticity of the oral region is well represented in Quennerstedt's 

 delineations reproduced at Figs. 43 and 44. 



The Trachelius striatiis of Dujardin * is apparently a fresh-water variety of the 

 genus Chceiiia ; its shape and proportions are identical with those of C. teres, but it is 

 of much smaller size. 



Fam. VII. TRACHELIIDiE, Ehr. 



Animalcules free-swimming, ovate or elongate, highly elastic, ciliate 

 throughout ; oral cilia slightly larger in size than those of the general 

 cuticular surface ; oral aperture situated at the base of a more attenuate 

 and often trunk-like anterior prolongation. 



Genus I. TRACHELIUS, Ehrenberg. 



Animalcules free-swimming, ovate or subglobose, the anterior portion 

 produced in a snout or trunk-like manner, the oral aperture being situated at 

 the base of this anterior prolongation ; pharyngeal tract apparently ramify- 

 ing within the interior of the body, and presenting the aspect of a branched 

 alimentary canal, such appearance, however, being entirely due to the 

 highly vacuolar or reticulate character of the internal sarcode or endoplasm ; 

 anal aperture postero-terminal ; cuticular surface entirely and finely ciliate, 

 oral cilia differing but slightly in size from those of the general surface. 



This genus is now limited to those forms only that coincide with Trachelitis ovum 

 in the possession of an apparent internally ramified alimentary tract. The numerous 

 other species formerly placed in it by the older writers are chiefly assignable to the 

 genera Amphileptns and Loxophyllum. 



Trachelius ovum, Ehr. Pl. XXVII. Fig. zZ. 



Body subglobose or ovoid, prolonged anteriorly in the form of a short, 

 flexible, trunk-like appendage, whose length does not exceed, and rarely 

 equals, the diameter of the body ; oral aperture succeeded by a short, 

 conical, longitudinally plicate phaiynx, which is apparently continued as a 

 wide, central, longitudinal and tubular prolongation, giving off at right 

 angles numerous smaller, lateral, ramifying diverticula ; cuticular cilia fine, 

 distributed in even longitudinal rows ; contractile vesicles numerous ; endo- 

 plast ovate or band-like, subcentral. Hab. — Bog water. 



The possession by this species of a complex and profusely ramifying oesopha- 

 geal canal, as first reported by Ehrenberg, and since maintained by Lieberkuhn and 

 Claparede and Lachmann, is not endorsed in this volume. In examples obtained 

 in bog water from Dartmoor, Devonshire, in August 1879, and examined by the 

 present author, the suspicion hitherto maintained that the endoplasmic substance 

 would be found to be highly vacuolate, somewhat as in Loxodes rost?-um, and thus 

 lend a branched, intestine-like appearance to the intervening granular sarcode, was 



* ' Histoire des Zoophytes Infusoires,' pl. vii. fig. 15, 1854. 



