OF TUE ROTATOEIA. 455 



fallen, in describing the linear seminal corpuscles that lie parallel to one 

 another about the outlet of the seminal vesicle to be bundles of muscular 

 fibres attached to the base of the penis, and acting as ^* ejacidatores seminis.'' 



The Enterojolea Hydatina (Ehr.) is, in Leydig's opinion, the male of Hydatina 

 senta : the reasons for this belief briefly are, that, according to Ehrenberg's de- 

 scription and figures, the Enteroj^lea has neither jaws nor teeth ; that its 

 ovary is homogeneous and granular ; that the animal is always smaller than 

 Hydatina senta ; and that among the eggs of this last-named species, those 

 developing into embryo Enteroplea were intermixed. Now each and all these 

 differential, and some of them very exceptional characters, are at once inter- 

 preted by assuming Enteroplea to be a male animal. Indeed, in no female 

 perfect Eotifer are the jaws wanting, and even in very young specimens the 

 ovary is not homogeneous, but contains many germinal vesicles or spaces. A 

 reference to Dujardin's description and engravings adds additional weight to 

 this opinion. This supposition has been confirmed, both by Leydig himself 

 Midler's Archiv, 1857, p. 404, and A. JSf. H. 1857), and by Cohn (Zeitschr. 

 1855, p. 451), and we would refer the reader to their memoirs for an ex- 

 tended description of this male being. By these researches, the testicle and 

 its contained spermatozoa, together with a male projectile organ, the absence 

 of a digestive apparatus, and other sexual peculiarities, have been satisfactorily 

 made out. 



In the case of Notoimnata granularis, the arguments for its male character 

 are, the absence of the maxillae, and probably of the ovary also — for neither 

 Ehrenberg nor Weisse could satisfactorily make out the existence of the latter, 

 — and, further, the presence, as the Berlin Professor points out, of two sorts of 

 eggs upon Notommata Brachionus, the smaller of which bring forth individuals 

 of the supposed different species, Notommata granularis. 



The evidence for the male nature of Diglena granularis (Weisse) is its 

 constant occiuTence in company with D. CatelUna, and the production of 

 two sorts of eggs by the latter, the smaller of which give birth to embryos 

 wanting the dental apparatus. Such imjierfect beings as the Diglena granu- 

 lans and the Notommata granularis were explained by Weisse to be immature 

 or premature embryos. " It is truly interesting," says Leydig, '' that Weisse, 

 at the time he wrote perfectly ignorant of male Rotifera, should arrive at the 

 conclusion that Notommata granularis, Diglena gramdaris, and Enteroplea 

 Hydatina were not distinct species, but the incomplete and toothless young 

 of the several species, Notommata Brachionus, Digleyia CatelUna, and Hydatina 

 senta.'''' It is added in a note — " Under the name Notommata gramdaris may 

 weU be associated together the veiy similar males as well of Notommata By^a- 

 chio7ius, as also of B. ureeolaris and B. Pala.'' A few notes in illustration 

 may be added from Cohn's account of the male of Brachionus ureeolaris 

 (Zeitschr. 1855, p. 471). This is much smaller and more active than the 

 females. Its rotary apparatus forms a wide ciliated rim ; but its cilia are not 

 turned inwards and downwards, as in the females, to enter the mouth, for no 

 such orifice exists : hence there is no maxillary head, no intestine, and no 

 gastric glands. In the place of those organs lies a large pyriform saccular 

 testicle, as much as y Ytnjth of an inch in length, incompletely filled with fine 

 dark corpuscles, which, when mature, acquire the characteristic figure and 

 swarming movements of spermatozoa. The wall of the testicle is excessively 

 thick, perhaps muscular, and is extended upwards mto a tliick cylindiical band, 

 which appears to serve as a medium of attachment to fix the gland above to 

 the region of the cephalic disk. At its posterior end, the testis presents a close 

 longitudinal striation, and is perforated by an aperture which opens into a 

 wide canal ending in the penis. This last-named organ has the aspect of a 



