GENUS PODOPHR YA. 817 



Podophrya Wrzesniowskii, S. K. PL. XLVI. FIG. 31. 



Body elongate-ovate or elliptical, about twice as long as broad ; pedicle 

 thick, subcylindrical, increasing slightly towards its point of junction with 

 the body, internally longitudinally, and externally finely transversely striate ; 

 tentacles very minute and slender, distinctly capitate, distributed irregularly 

 over the entire peripheral surface, but most abundant anteriorly ; contractile 

 vesicles two or three in number ; endoplast irregularly ovate ; numerous 

 minute spherical vacuolae containing refringent granules usually present 

 towards the posterior extremity. Length of body 1-400". 



HAB. Fresh water, on the elytra of the aquatic Coleopteron Hydroporus 

 picipes. 



This species has been recently figured and described by Wrzesniowski * and 

 referred by him to the Podophrya Leichtensteinii of Claparede and Lachmann, and 

 Acineta (Podophrya) hyphydri of Stein. A comparison, however, of the accounts and 

 illustrations of these respective forms has convinced the author that we have in the 

 present instance a type differing considerably from the one last-named. The 

 characters which serve to distinguish this present form from Stein's species may be 

 thus summarized : The body, while exhibiting a somewhat similar but at the same 

 time more regularly elliptical contour, is mounted on a pedicle which does not 

 expand widely at its point of junction with the body as in P. Leichtensteinii, and 

 whose surface is finely striate transversely instead of coarsely wrinkled. The 

 characters afforded by the tentacula are still more decisive, for while in Stein's 

 species they exhibit a distinct fascicular arrangement and are confined to the anterior 

 region of the body, in the present one they are distributed without any definite 

 arrangement throughout the peripheral surface ; individually examined, the irregu- 

 larly scattered tentacles are further much more minute, their proportionate size 

 with relation to the body of the animalcule being about half that of P. Leichtensteinii. 

 These dimensions, associated with their distinctly capitate extremities, contrast in a 

 marked manner with the slender non-capitate appendages of the species with which 

 Wrzesniowski has proposed to identify it. The presence of the numerous vacuolae 

 with their enclosed refringent granules appears to afford an additional and permanent 

 feature of this species that would scarcely have been overlooked by Stein in his 

 account of P. Leichtensteinii. Being unable in face of these highly divergent 

 characteristics to unite under one specific title the two forms here submitted to 

 comparison, the author has much pleasure in associating with the type requiring 

 a new specific title the name of the investigator to whom we are indebted for its> 

 discovery, and who has proved himself so industrious a worker in this field of 

 biological research. Wrzesniowski records, in connection with the contractile 

 vesicle of this type, a distinct tubular exit similar to that of Dendrocometes paradoxus, 

 Acineta opercularice, and other representatives of the same order, as also that the 

 same vesicle is not always constant in its form or position, sometimes breaking up 

 in a fragmentary manner. This latter circumstance is rightly held as yielding con- 

 clusive evidence of the non-possession by this structure of a distinct membranous 

 wall, or its occupation of a distinctly differentiated interspace in the substance of 

 the parenchyma. Under high magnification, as in P. Leichtensteinii, the species 

 presents a well-developed cuticular layer, but this membrane is not separated from 

 the subjacent parenchyma so as to constitute an independent external pellicle or 

 lorica, as among the true Acinetcz to which Wrzesniowski has proposed to refer it. 



1 Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxix. p. 268, 1877. 



VOL. II. 2 A 



