FLOSCULARIADvE. 59 



duct which divides into two lateral canals. Each canal runs slantingly up to a coil at 

 the side of the body below the cup, and thence sends a branch into the dorsal surface of 

 the cup, anastomosing with its fellow above and below the nervous ganglion (PL 1), 

 fig. ib), and bearing two vibratile tags on each side of it. The nervous ganglion is a 

 four-side organ in the dorsal wall of the cup ; it sends out a nerve thread at each 

 corner, the lower pair passing to two lateral antennae. No eyes are visible in the adult. 

 The young embryo is developed in the egg in the body of the parent. When hatched, 

 it is a free-swimming Rotiferon (PL D, fig. id), with a truncate, ciliated, anterior ex- 

 tremity, and with the cloaca, at the ciliated posterior extremity, surrounded by a mem- 

 branous ring. There are two red eyes, but the characteristic coronal cup is as yet 

 undeveloped. The male, which has a ciliated foot, is so like those already described, 

 that Herr Metselmikoff s drawings supersede description (PI. D, fig. 4e). 



Prof. Leidy described in 1857 (loc. cit.) a new Rotiferon, "destitute of wheel- 

 organs," which he named Dictyophora vorax. He obtained, however, some fresh 

 specimens in 1884, and is now of opinion (loc. cit.) that the animal is identical with 

 Apsihts lentiformis, and that the discrepancies between his account and Herr Metselmi- 

 koff s are due to the wrinkled condition of his first specimens, which had been forcibly 

 removed from the glass sides of an aquarium. 



Mr. S. A. Forbes also described (loc. cit.) a Rotiferon found in a neglected aquarium, 

 and "wholly destitute of cilia or other vibratile structure." He called it Cupelopagus 

 buciiiedax, and gave a very characteristic figure of its side view. I have little doubt 

 that this also is Apsilus lentiformis. 



Length. Maximum about -, 1 ,, inch. Habitat. On water plants, Giessen (Metselmikoff) ; 

 Fairmount Park, and Schuylkill river, U. S. i Leidy). 



* Apsilus bipeea, Foulke. 

 (PI. D, fig. 5.) 



Apsilus bipera .... Foulke, Proc. Acad. Nat. Sci. Pa. 1SS4, pp. 37, 50, 



pi. i. figs. 4, 7. 

 Apsilus lentiformis . . . Leidy, Proc. Acad. Nat. Sci. Pa. 1834, p. 50. 



Miss S. G. Foulke, who discovered this Rotiferon, is of opinion that it differs from 

 Apsilus lentiformis sufficiently to warrant its being regarded as a distinct species ; the 

 points of difference being the shape of the cup, the absence of ganglion, the presence of 

 a " second stomach," and the ciliation of the cup. 



If A. bipera really has two stomachs, one above the jaws and the other below them, 

 and each a closed sac with walls distinct from those of the body-cavity, then it would 

 not only be a new species, but also a perfectly unique one among the Rotifera. It is 

 evident that further investigation is wanted on this and other points ; especially as 

 Prof. Leidy is of opinion that Apsilus bipera, Dictyophora vorax, and Apsilus lentiformis 

 are all the same animal. 



But whether Miss Foalke's species be a new one or not, to her is due the discovery 

 of a true ciliary wreath within the coronal cup. It consists of two gradually narrowing 

 ridges, fringed with long cilia, and running up the inside of the dorsal surface of the cup 

 (fig. 5a). Short diagonal lines of finer cilia can be indistinctly seen between the larger set. 

 This ciliary apparatus is quite unique in position.; and, if A. bipera and J. lenti- 

 formis are the same, it is curious that Miss Foulke should have missed the nervous 

 ganglion, and that Herr Metschnikoff should have missed the ciliary ridges. 



Length. Up to A a inch. Habitat. Water-plants in Fairmount Park, U.S. (Miss 

 Foulke'. 



