568 ORDER HOLOTRICHA. 



Anoploplii'ya pachydrili, Clap. sp. 



Body irregularly ovate or subpyriform ; widest and truncate posteriorly, 

 pointed and narrowest anteriorly ; two or three contractile vesicles forming 

 a row on each lateral border ; endoplast not observed. Length 1-350". 



Hab. — Marine, within the intestine of PacJiydriliis verrucosus. 



Genus III. HAPTOPHRYA, Stein. 



Animalcule mouthless, ovate or elongate, the anterior extremity modified 

 so as to form an adhesive sucking-disc ; the remaining cuticular surface 

 ciliate ; contractile vesicle and endoplast conspicuous, the former mostly 

 canalicular. Entirely endoparasitic. 



Stein, in his original subdivision of the somewhat heterogeneous assemblage of 

 animalcules previously referred to the single genus Opalina, into four groups of 

 corresponding taxonomic value, proposed to distmguish those characterized by the 

 possession of an adhesive acetabulum by the title of Discophrya. This generic 

 name he introduces in his essay relating to the subdivision of the Holotrichous 

 Infusoria contributed to the ' Sitzungsberichte der konigl. bohmischen Gesellschaft 

 der Wissenschaften' for the year i860, and uses also in his sketch of the Holotri- 

 chous order contained in vol. ii. of his ' Organismus der Infusionsthiere,' published 

 in the year 1867. In his final classification table of the Cihata, reproduced at p. 2 10 * 

 of vol. i., he, however, without any explanation, substitutes in its place that of 

 Haptophrya. This name, having been since adopted by other Continental 

 authorities, is accordingly preferentially adhered to in the present treatise. A 

 distinctive feature of the genus, shared also by some few members of the armed 

 Hoplitophrym, is connected with the contractile vesicular system. In the previous 

 genus Aiwplophrya, this is generally found to take the form of one or two linear 

 series of independently pulsating spheroidal vacuoles, while in the present one, 

 Haptophrya, it — in all species so far knowTi — consists of a single canal-like reservoir 

 that is produced throughout the greater e.xtent of the creature's body. Under 

 abnormal conditions, such as the transfer of the animalcules to pure water, it has 

 been shown by Ray Lankester, in the case of Aiwplophrya naidos, that two or more 

 of the normal spheroidal vesicles may run together, producing a more or less 

 extensive canal-like lacuna. There can, therefore, be but little doubt that the 

 characteristic canal-like contractile vesicle of Haptophrya represents a more highly 

 differentiated modification of the linear series met with in the preceding genus. 



Haptophrya planariarum, Siebold sp. Woodcut, p. 569. 



Body wedge-shaped or subcylindrical, about six or seven times as long 

 as broad ; rounded and widest anteriorly ; the posterior extremity pointed ; 

 the anterior region bearing a semicircular adhesive disc, the central portion 

 of which is apparently naked, while its outer margin is provided with a 

 fringe of cilia of larger size than those which clothe the remaining cuticular 

 surface ; contractile vesicle canal-like, extending nearly the whole length 

 of the body ; endoplast elongate-ovate, granular. Length of body 1-36". 



Hab. — Intestinal cavity of various Planarians, including more especially 

 Planaria torva. 



* By accident, the two generic names Hoplitophrya and Haptophrya have in this table been 

 misspelt Hoplophrya and Haptophrya, — Ed. 



