8 10 ORDER TENTACULIFERA-SUCTORIA. 



Urostyla, it is difficult to determine. The position taken up by Spharophrya pusilla 

 with reference to an allied ciliate type, namely externally, but close to the oral 

 aperture, favours the supposition that in other instances, like the present, they may 

 prefer to cultivate a still more intimate acquaintance with the commissariat of their 

 foster-parent. It is at all events certain that they are not incepted as food-material 

 or destined to be digested, as after being so enclosed, they are able to bore their 

 way out again through the parenchyma of their host, in either their adult condition 

 or in the form of ciliated embryos. 



Sphserophrya stylonychlse, S. K. 



Body subspherical, suckers short and slender, few in number, thinly 

 scattered throughout the periphery ; contractile vesicle single ; endoplast 

 spherical. Diameter 1-700". Embryos ovate, about three times as long 

 as broad, having a dense covering of cilia in addition to the scattered 

 suckers, which they equal or exceed in length. 



HAB. Fresh water, associated with Stylonychia mytilus. 



The shorter proportions of the embryos of this species, as well as the distinct 

 specific nature of the host accepting the form as parasitic seem to distinguish it 

 from Spharophrya Urostylce last described. In accordance with the views originally 

 entertained but since abandoned by Stein, this form was presumed to be the acinete 

 embryo of Stylonychia mytilus. 



Sphserophrya sol, Mecz. PL. XL VII. FIGS. 6 AND 7. 



Body spherical ; tentacles numerous, protruding from all parts of the 

 periphery, extensile to a length exceeding the diameter of the body ; con- 

 tractile vesicle single ; endoplast ovate. Diameter 1-500". 



HAB. Parasitic within ParawKzcium aurelia. 



The multiplication of the species by transverse fission accompanied by the 

 subdivision of the endoplast is recorded by Mecznikow.* Preparatory to this mode 

 of increase the body of the animalcule assumes an elongate-ovate contour. Being 

 unaware, apparently, of Mecznikow's work, E. Maupas has more recently proposed 

 to confer upon this type the title of Sph&rophrya paranuzciorum. A closely allied, 

 if not identical type has been observed by both Stein and Claparede and Lachmann, 

 as an endoparasite of Paramcecium bursaria, and has, in both instances, been treated 

 as an embryonic condition of that Holotrichous form. 



Sphserophrya stentorea, Maupas. PL. XLVL FIG. 7-9. 



Body subspheroidal, ovate or elongate, frequently with one or two annular 

 constrictions; the posterior end of the body bearing eight or ten short, 

 irregularly scattered, capitate tentacles, the opposite extremity usually 

 clothed with long fine cilia ; endoplast ovate, developed toward the anterior 

 region of the body; contractile vesicles two in number, located posteriorly to 

 the endoplast. Length 1-600". 



HAB. Fresh water, occurring as an endoparasite of the Trumpet Ani- 

 malcule, Stentor Rceselii. 



This type was originally figured and described by. Stein as an embryonic 

 condition of the Infusorian with which it is found associated. It would seem highly 



' Miiller's Archiv fur Anatomic u. Physiologic,' 1864. 



