392 PROCEEDINGS OF THE ACADEMY OF [May, 



The young are free-swimming, but it is the rule that the aduhs Uve 

 permanently attached within a gelatinous tube. The exceptions 

 are the pelagic species Floscularia pelagica Rousselet, atrochoides Wier- 

 zejski, libera Zacharias. Since some of these swim carrying a gelati- 

 nous tube, it is probable that they were derived from sedentary forms. 

 All the known species are restricted to fresh water, except two which 

 are eurhyaline. 



The sexes are dimorphic, and the small males represent individuals 

 arrested in their development (they have considerable resemblance to 

 immature females), and also degenerative in structure (shown by the 

 absence of the alimentary tract). 



The whole structure is bilaterally symmetrical; even the unpaired 

 dorsal sense-organ has a pair of nerves, which, as Zelinka has correctly 

 argued elsewhere, points to its original paired condition. The radiality 

 evinced by the arrangement of the coronal lobes is referable to the 

 sedentary mode of Hfe. 



Finally, in contradiction to most other Rotatoria, in most species that 

 have coronal ciha, these do not serve to create food currents, but are 

 stiff and more like pseudopodia. 



Literature Cited. 



CuBiTT, C. Floscularia coronetta. Month. Micr. Journ., 2, 1869. 



Idem. Observations on Some Points in the Economy of Stephanoceros. Ibid., 



3, 1870. 

 Idem. On the Homological Position of the Tube-makers. Ibid., 8, 1872. 

 DixoN-NuTTALL, F. R. On the Male of Stephanoceros Eichhornii. Journ. 



Roy. Micr. Sac, 1896. 

 DoBiE, W. M. Description of Two New Species of Floscularia with Remarks, 



Ann. Mag. Nat. Hist., (2), 4, 1849. 

 Idem. Stephanoceros Eichhornii. Ann. Anat. Physiol., 1, 1854. 

 DuJARDiN. Histoire naturelle des Zoophytes. Infusoires. Suites a Buffon, 



1841. 

 Eckstein, K. Die Rotatorien der Umgegend von Giessen. Zeit. wiss. ZooL, 



39, 1884. 

 Ehrenberg, C. G. Ueber die Entwickelung und Lebensdauer der Infusions- 



thiere, etc. Abh. Akad. Wiss. Berlin, 1832. 

 Idem. Dritter Beitrag zur Erkenntniss grosser Organisation in der Richtung des 



kleinsten Raumes. Ibid., 1835. 

 Idem. Die Infusionsthierchen als vollkommene Organismen. Leipzig, 1838. 

 EiCHHORN, J. C. Beytrilge zur Naturgeschichte der kleinsten Wasserthiere. Dan- 

 zig, 1775. 

 Forbes, S. A Remarkable New Rotifer (Cupel opagis bucinedax). Amer. 



Month. Micr. Journ., 3, 1882. 

 FoxjLKE, S. G. On a New Species of Rotifer, of the Genus Apsilus. Proc. Acad. 



Nat. Sci. Philadelphia, 1884. 

 Gast, R. Beitriige zur Kenntniss von Apsilus vorax (Leidy). Zeit. wiss. ZooL, 



67, 1900. 

 GoLDFUSS, G. A. Handbuch der Zoologie. Niirnberg, 1820. 



