GENUS SPH^ROPHRYA. 809 



when extended, equal to that of the diameter of the body, produced from 

 all parts of the periphery ; contractile vesicles one or two in number ; endo- 

 plast spherical, finely granulate, excentric : parenchyma usually granular 

 and opaque. Diameter of body 1-600''. Hab. — Fresh water, Algeria. 



The discoverer of this species, M. Maupas, in figuring and describing it,* 

 has placed on record some interesting data in connection with the structure of 

 the tentacles and the phenomena of food-ingestion. On many occasions it was 

 observed by him that the suctorial appendages exhibited during their extended 

 state a greater or less number of oval or spherical dilatations or varicosities, these 

 varicosities from time to time altering in shape or totally disappearing. Submitted 

 to high magnification it was shown that these dilatations were composed only of the 

 external or cortical element of the tentacles, the internal or axial part passing 

 straight through them, and remaining undisturbed by the alteration of contour that 

 they undergo. Maupas has been thus led to the conclusion that in this SphiBrophrya 

 magna and certain other Acinitid^e the tentacles consist of a central axial filament 

 of amorphous sarcode upon which is superimposed an external layer of the same 

 element of much more delicate consistence, and possessing marked polymorphic 

 properties. He further anticipates that the button-like inflation of the extremity of 

 the tentacles in this and kindred species consists of an excurrent spheroidal mass of 

 the axial sarcode only, such interpretation being supported by his observation that 

 on a ciliated infusorian coming into contact with its substance, but succeeding in 

 escaping, this normally spheroidal mass presented under high magnification, as shown 

 at PI. XL VII I. Fig. lb, d. lacerated or ragged contour. By introducing into the 

 same water an abundant supply of the ciliate type Colpoda parvifrons and Cydidiuin 

 glaucoma, the Sphaerophryas fed upon them voraciously, one example having been 

 observed by Maupas to seize and devour simultaneously no less than half-a-dozen of 

 these Holotrichous animalcules. The phenomena of ingestion, as described by this 

 investigator, are referred to at length in the section devoted to the general descrip- 

 tion of the Tentaculiferous class. In common with other species of the genus, 

 SphcErophrya magna was observed to multiply abundantly by transverse fission, the 

 body becoming first elongated, then centrally constricted, and finally separating into 

 two subequal moieties. While one of these products soon assumed the spheroidal 

 contour and normal aspect of an adult zooid, the other one, withdrawing its tentacles, 

 became yet more elongated, its surface grew rugose, and ultimately developing fine 

 cilia at its anterior extremity, it swam away, the data observed being thus closely 

 analogous to those previously reported by the same authority of Podophyra libera. 



Sphserophrya urostylae, Maupas. Pl. XLVI. Figs. 3-5. 



Body subspherical ; suckers slender, their length about equal to the 

 diameter of the body, scattered irregularly over the surface of the periphery ; 

 one or two contractile vesicles ; endoplast spherical. Diameter of body 

 1-500." Embryos elongate-ovate, from three to four times as long as 

 broad, densely clothed with cilia, which exceed in length the scattered 

 suckers. Hab. — Fresh water, associated with Urostyla grandis. 



The above title, originally adopted by the author in manuscript, has been 

 recently bestowed by Maupas on the species figured and described by Stein as the 

 Acineta-phase of Urostyla grandis, and with which last-named type, according to the 

 representations of that authority, it is found associated in vast numbers ; whether, 

 however, these minute globular Acinetce occupy the digestive cavity of their host 

 of their own accord, or are engulfed within the same by the ciliary currents of the 



* "Contribution a I'fitude des Acinetans," 'Arch, de Zoologie Experimentale,' torn, ix., 

 Nov. 3. 1881. 



