5 1 4 ORDER HOLOTRICHA. 



Tillina magna, Gruber. Pl. XXXII. Fig. 13. 



Body subreniform or bean-shaped, compressed, rather over twice as long 

 as broad ; an irregular, broad, lobate process developed from the dorsal 

 aspect of the posterior extremity and interrupting the symmetry of this 

 region ; oral aperture ventral, subcentral, followed by a tubular, strongly 

 recur\'ed pharj'nx, whose walls are conspicuously ciliate throughout ; oral 

 and phar}-ngeal cilia considerably larger than those covering the general 

 cuticular surface ; cuticular surface smooth, or finely and sparsely striate 

 longitudinally, its deeper layer apparently striate radially, an aspect due 

 most probably to the enclosure of trichocysts ; endoplast elongate-ovate, 

 situated in the anterior body-half; contractile vesicle posteriorly located, 

 intrenching partly on the irregular lobate process. Length 1-125". 



Hab. — Fresh water. 



This species, described by Dr. August Gruber, together with several other 

 interesting forms, in the 'Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxxv., 1879, 

 and translated in the 'Journal of the Royal Microscopical Society ' for April 1880, is 

 regarded by its discoverer as exhibiting a tj'pe of structure intermediate between 

 Paramacium and Colpoda. In the peculiar form of phar)Tix, however, it much 

 more closely approaches Comlwphthirus, but is necessarily referred to the present 

 family group on account of the more conspicuous development of the oral cilia. 

 Reproduction accompanied by encystment and subdi\ision into four equal spore-like 

 masses after the manner of Colpoda^ has been obsen-ed. In the accompanying 

 drawing the anterior and posterior regions have been accidentally reversed. 



Fam. VI. TEACHELOCERCIDiE, S. K. 



Animalcules free-swimming, flask-shaped or elongate, soft and flexible, 

 ciliate throughout, the oral cilia slightly exceeding in size those of the 

 general cuticular surface ; the anterior extremity usually prolonged in a 

 neck-like manner, an annular groove or furrow often present near the apical 

 extremity ; oral aperture terminal or subterminal. 



Genus I. TRACHELOCERCA, Ehrenberg. 



Animalcules highly elastic and changeable in form, the anterior portion 

 produced as a long, flexible, narrow, neck-like process, the apical termination 

 of which is separated by an annular constriction from the preceding part, 

 and is perforated apically by the oral aperture ; the entire cuticular 

 surface finely and evenly ciliate, a circle of longer cilia developed round 

 the oral region. Anal aperture postero-lateral or subterminal. Contractile 

 vesicles usually multiple, irregularly distributed. Inhabiting fresh and salt 

 water. 



The diagnosis of the genus Trachdoccrca as above given, and as constructed in 

 accordance with the results of more recent investigation, differs materially from that 

 first introduced by Ehrenberg. In accordance with the representations of this last- 

 named authorit\% the cuticular surface of the animalcules of this genus was entirely 

 devoid of cilia, and the oral aperture, instead of being situated at the apical extremity 

 of the anterior neck-like prolongation, as is now determined, was pronounced to be 

 located in the annular groove that separates die extreme anterior portion from the 



