618 



SYSTEMATIC HlSTOEY OF THE INFTJSOEIA. 



Genus TRACHELIUS (XXIV. 287-290).— Body ciliated ; mouth simple, 

 destitute of teeth, is seated on one side at the base of the very much elon- 

 gated upper lip or proboscis. Cilia are absent in three species. In four 

 species coloured food has been received, and in three the discharging orifice 

 detected. It has also a coUapsed oesophagus, visible only during the passage 

 of food. Two species increase by transverse self- division. 



This genus forms a member of the family " Trichodiens " (Trichodina) 

 (Duj.), along with Trichoda and genera named Acineria, Pelecida, and 

 I)ile2:)tus. 



The account he gives of the animals differs much from the foregoing. Ac- 

 cording to it, Trachelius is destitute of a contractile or reticulated integu- 

 ment, and is composed of a muco-gelatinous substance (sarcode) containing 

 granules, which are oftentimes agglomerated in the form of nodules, disposed 

 in rows. The apparent oviposition in T. Ovum and T. Meleagris was nothing 

 more than the breaking up of part of the animalcule by " diffluence," and 

 the supposed ova only particles of '' sarcode." 



" The cilia at the anterior extremity are larger than those on the rest 

 of the body. Posteriorly a large vacuole is often to be seen. There is no 

 distinct mouth." 



The last statement is contradicted by recent investigations, which prove 

 that the animalcules belonging to this family have a mouth, and some of 

 them, at least, an anus. 



Trachelius Anas {Trichoda Anas et 

 Index, M.)(xxiv. 287-289).— White, cla- 

 vate, and cylindrical; proboscis thick, 

 obtuse, not half the length of body; 

 mouth situated close to the base of the 

 proboscis. In exposed infusions, and 

 fi-eshwater swamps, amongst Confei-vse. 

 The interior often contains green (chlo- 

 rophyll) vesicles. 1-280" to 1-120". 



T. vorax. — Clavate-ovate, turgid, co- 



lour 



proboscis thick, obtuse, 



shorter than half the body ; mouth situ- 

 ated near the middle of the body, and 

 not at the base of the proboscis. Amongst 

 Confervc^. 1-120". 



T. Meleagris. — Compressed, lanceolate, 

 often curved in the form of the letter S ; 

 proboscis thick, obtuse, shorter than half 

 the body. 1-96" to 1-60". 



Ehrenberg described in this species a 

 red-coloured fluid which he called bile, 

 and a row of ten to twelve vesicles along 

 the back, which he concluded to be sto- 

 mach-cells filled with red gastric juice. It 

 is now, however, admitted that these cells 

 are really contractile, and fonn a vascular 

 chain. The nucleus is oval, with a cen- 

 tral constriction. Dujardin adopted this 

 species as one form of a new genus, 

 Loxophyllmn, hereafter described in the 

 family Colpodea. 



T. Lamella (Kolpoda Lamella, M.) 

 (xx^^. 24 a, b). — Depressed, laminar, 

 elongated, linear-lanceolate, often trim- 

 cated anteriorly and rounded ; margin 

 ciliated (Dujardin says, only in front). 



Ehrenberg considers this form may be no 

 other than the young condition of A}n- 

 philejjtus Fasciola ; and Perty woidd add, 

 of Spathidimn hyalijium. In sea-water. 

 1-900" to 1-200". 



T. Anaticula. — White, small, ovate, 

 pyiiform, attenuated and diaphanous an- 

 teriorly. Dujardin believes he has seen 

 several of these animalcules become by 

 simple contact agglutinated together, — 

 a circumstance which woidd indicate the 

 absence of a true integument. Amongst 

 Conferv£e. 1-570" to 1-280". 



T. (?) tricJiopJiorus ( Vibrio strictus, M.) 

 — Cylindrical, changeable, often clavate; 

 proboscis capitate, of the form of a very 

 delicate whip. 1-1200" to 1-430". 



T. (?) glohdifer. — Spherical, hyaline, 

 with a very delicate whip-like acute pro- 

 boscis. Ajnongst Confervas. 1-200". 



T. Ovum (xxiv. 290). — Large, ovate, 

 wide or campanidate anteriorly; pto- 

 boscis short, in the form of a beak ; con- 

 tractile vesicles numerous. " In no in- 

 fusorial animalcule," says Ehrenberg, " is 

 the alimentary canal so easily seen as in 

 this ; the large mouth and contractile 

 vesicle, Ijang over the lower part of the 

 alimentary canal, are equally evident; 

 nmnerous smaU digestive cells and ova- 

 granules appear in every part. " It is in 

 this species that LieberkUhn and Lach- 

 mann have latterly described the exist- 

 ence of an arborescent, ramified digestive 

 canal, quite distinct from the cl^ar round 

 spaces in the parenchyma of the body, 



