Oy THE EOTATORIA. 463 



remarks, premising that the detection of spermatic particles in one species 

 furnishes a criterion in pronouncing upon the signification of some other 

 bodies : — " I have heretofore mentioned my idea that the hairy corpuscles of 

 Lacinulana (occupying the general cavity of the body, and impelled hither 

 and thither by its movements) are seminal particles : although this is still 

 questionable, yet these presumed parasites of Lacinularia must, I beHeve, be 

 still rather looked upon as unequivocal spermatozoids. The form and struc- 

 tiire, moreover, of the bodies figured by Huxley, and doubtfully called by 

 him spermatozoa, have an evident affinity with the seminal elements of No- 

 iommata Sieboldu. It also seems to me probable that the spermatozoids 

 portrayed by Kolliker in Megcdotrocha are really such, and that the animals 

 in wMch they are found should be esteemed as previously impregnated 

 females. I moreover consider that the illustrations furnished by Ehi-enberg 

 of Conochilus volvox, show an individual with two spermatozoa; and the 

 account referring to it, in which he says ' I lately saw oscillating, very pe- 

 culiar, gill-Kke organs, in the form of two spirally-twisted bands, at the pos- 

 terior extremity of the body,' also speaks in favour of this signification. The 

 entire delineation of these ^ spiral gills ' might replace very well that of the 

 peculiar seminal elements with undulating membranes." 



Afterwards, when speaking of the parasites of Eotatoria, Leydig observes 

 that ha\ing formerly erroneously described the seminal corpuscles of Lacinu- 

 laria as parasites, he must now, on the other hand, class the once-presumed 

 spermatic particles with parasitic organisms. 



In the course of subsequent researches on Hydatina senta (Miiller's ^rcZi^i;, 

 1857, p. 104), Leydig has discovered the same sort of structm^es in that ani- 

 mal. He writes — " They are globular bodies with sharp outlines ; and their 

 margin looks as if clothed with fine haii^s. Towards the end of March, the 

 entii-e abdominal cavity was in many specimens so filled with them that the 

 animals presented a white appearance by reflected light ; yet the animals so 

 affected swarm about just as briskly as the others." This repletion with such 

 particles appears to us to intimate that they cannot be spermatozoa, either 

 generated within the beings themselves or received fi'om without from male 

 animals. Indeed their oceuiTence within the abdomen of Hydatina senta 

 is of itself an argument against their being spermatozoa derived from a male 

 gland within, inasmuch as this species is proved to be impregnated by its 

 own male partner, formerly known as the Enteroplea Hydatina, The ques- 

 tion presents itself, whether they can be derivable from the food, as products 

 of digestion or chyle-globules. 



The search for male Rotatoria has led the occasional connexion of two in- 

 chviduals to be noticed, and to be explained as of a sexual character. Periy 

 noticed two individuals of Colurus uncinatus, and two of Lepadella ovalisy in 

 union. But such connexions may rather be considered accidental ; for Perty re- 

 marked a Colurus so attached to LepadeUa, and a Chmtonotus Larus to Lepadella 

 ovalis. Cohn has had his attention directed to the same cii'cumstance, and 

 remarks that two Rotatoria of the same or even of a different species are 

 very often to be seen attached together, sometimes by the back, at others by 

 the abdomen, at others by the pseudopodium, and to swim about together for 

 a length of time. This he has seen in Diglena, Colurus, and LepadeUa ; it 

 has, however, no connexion with the reproductive function. 



Of the Duration^ and Conditions of Life of the Rotatoria, and of theer 

 Habitats and Distribution. — It is next to impossible to determine, by direct 

 observation, the duration of life among the Rotatoria when placed under 

 natural and favoui^able conditions. Many may well be supposed to survive 

 from their birth in the spring until the winter, and not a few even through 



