Minute Anatomy of the Infusoria. 479 



endeavour to show the Gregarina to be larvae of higher animals, 

 and especially to connect them with encysted Nematoid worms. 



For many reasons this appears to me to be a vain attempt. I 

 will here bring forward only a few arguments. I am acquainted 

 with Gregarina of such peculiar forms, that one requires a very 

 strong imagination to deduce them from Nematoidea, or to sup- 

 pose they can pass into these. The encysted Nematoidea are 

 always found in the cavity of the body of insects, never in their 

 intestinal canal, where alone encysted Gregarina are to be found. 



In the few insects which contemporaneously with the Grega- 

 rina: lodge encysted Nematoidea, the cyst which incloses the 

 latter is always a well-organized structure of cells with clearly 

 marked nuclei, upon and in which numerous trachea? are distri- 

 buted. This tissue agrees perfectly in its finer structure with 

 the fatty mass of insects. The cyst of the Nematoidea is there- 

 fore plainly a product of the vital activity of the insect, not the 

 exudation of the inclosed worm. The cyst of the Gregarina, on 

 the other hand, is always an amorphous mass, and like the cyst 

 of VoriicelLe, nothing but an excretion of the included Gregarina. 

 If, therefore, encysted Nematoidea change into Gregarina or vice 

 versa, their cyst must undergo a metamorphosis, which perhaps 

 no one will assume, and of which as yet no observer has seen 

 anything. Perhaps I shall be able to find leisure for the pub- 

 lication of my complete researches upon the Gregarinidse, and 

 then the doubts opposed to my views may perhaps be resolved. 



The remainder of the memoir contains descriptions of several 

 new forms of the Vorticellinae, principally found upon Gammarus 

 pulex, Cyclops minutus and Asellus. The first — 



Spirochona gemmipara, has inflexible parietes, and is closely 

 allied to Epistylis. 



Dendrocometes paradoxus is a very remarkable body with se- 

 veral radiating branched arms, almost like some Xanthidia. Stein 

 supposes it, with great probability, to be the Acineta-form of 

 Spirochona. 



Lagenophrys is nearly allied to Cothurnia. Three species of 

 it are described, from the legs of Cyclops, gill-laminae of Asellus, 

 and legs of Gammarus. One of these, L. nassa, is remarkable 

 for having an armed mouth like that of Nassula. 



The most important physiological points are : that the germ- 

 nucleus of Spirochona contains a clear nucleated vesicle, but 

 otherwise answers to that of other Yorticellince ; — that in the 

 oblique fission of Lagenophrys the anterior half of the animal 

 goes on moving and feeding, and is seen to contain globules of 

 nutritive matter, while the posterior half never contains any, but 

 consists internally of a homogeneous finely granular parenchyma, 

 in which nothing more is to be seen than a median contractile 



