502 ORDER HOLOTRICHA. 



Fam. HI. TRACHELOPHYLLID-S3, S. K. 



Animalcules free-swimming, ciliate throughout, more or less flask- 

 shaped ; oral and cuticular cilia alike, the oral aperture perforating the 

 extremity of the narrower anterior region, which is frequently highly 

 elastic and extensile. 



GENUS I. TRACHELOPHYLLUM, C. & L. 



Animalcules elastic, flattened, lanceolate or flask-shaped, having an 

 attenuate neck-like portion, the apical extremity of which is separated by 

 an annular constriction from the preceding part, and is perforated at its 

 apex by the oral aperture, as in the genera Lacrymaria and Trachelocerca, 

 but has no circlet of larger cilia ; pharyngeal passage tubular, conspicuously 

 developed ; contractile vesicle single, situated close to the postero-terminal 

 anal aperture. 



Claparede and Lachmann have founded the genus Trachelophyllum on the type 

 first described by Perty under the title of Trachdius apiculatum, separating it from 

 the last-named generic group on account of the terminal position of the oral aperture. 

 The animalcules are further distinguished from those of Lacrymaria, which they still 

 more nearly approach, by their compressed form and the absence of the annular 

 circlet of stouter cilia at the anterior or oral region. As a consequence of their 

 flattened contour, their movement in the water differs considerably from those of 

 the cylindrical Lacrymaria. This in the type-species, T. apiculatum, consists 

 chiefly of a smooth, gliding motion, after the manner of Chilodon and Loxo- 

 phyllum, in place of rotation on their axis as obtains in Lacrymaria and Phialina. 

 The neck in Trachelophyllum, while possessing a considerable amount of elasticity, 

 is inferior in this respect to Trachelocerca. 



Trachelophyllum apiculatum, Perty sp. PL. XXVI. FIGS. 61 AND 62. 



Body flattened, lanceolate ; neck long, slender, and highly extensile, 

 nearly equal in length to the body, perforated throughout the greater 

 portion of its length by a narrow, straight, somewhat obscure pharyngeal 

 tract, the walls of which are faintly striate longitudinally ; cuticular surface 

 entirely but thinly clothed with moderately long cilia, whose action is 

 somewhat irregular and independent ; contractile vesicle single, spherical 

 or rosette-shaped, posteriorly situated ; endoplasts multiple, ovate, two or 

 four in number. Length of body 1-144." HAB. Pond water. 



This animalcule is identical with the Trachelius apiculatum of Perty. From two to 

 as many as four nuclei or endoplasts were observed in the specimens as examined 

 by Claparede and Lachmann, though the former and smaller number only is 

 ascribed to it by Wrzesniowski. The character and varied aspect of the contractile 

 vesicle under the respective conditions of systole and diastole, and during the 

 passage of excreta through the terminal anal aperture, has formed the subject 

 of careful investigation by the last-named authority,* the results arrived at yielding 

 the strongest possible evidence in demonstration of the non-possession by this 



* A. Wrzesniowski, "Anatomic der Infusorien," ' Archiv fur Mikroskopische Anatomic* 

 Bd. v., 1869. 



