858 Bombay Branch Royal Asiatic Society : — 



remarkable feature about them is, that the largest contain, among 

 their granular contents, several smaller cells filled with a brownish- 

 yellow fluid, which are set free when the parent perishes, and seem 

 to serve some other purpose than that of reproduction. These 

 spherical cells appear to the author to be biliary organisms, for they 

 hue the stomach of the binocular and blind Planarice, where the 

 large ones have a lash of from forty to fifty cilia projecting from one 

 point of their circumference, which keep up a continued circulation 

 of the gastric contents by their motion, like that observed in the 

 Infusoria. Of the use of these organs, for which the author pro- 

 poses the term ** spherical cells," he is unacquainted, further than 

 that there are many points about them which strikingly ally them to 

 the hepatic cells of higher animals. 



Fesicula, or " Contracting Vesicle.''^ — This is a vesicular organ 

 presenting a hyaline aspect which appears and disappears rhythmi- 

 cally. Its services are excretory, and in Paramecium aurelia, where 

 it is double, each vesicle has a set of radiated lines round it, which 

 lines extend across the body, and consist, respectively, of a chain 

 of fusiform sinuses. In the Rhizopoda especially the vesicula 

 obtains a great plurality, and in Amoeba, sometimes, the sarcode 

 appears to be filled with such vesicles, which not only now and then 

 burst into the large one or vesicula, but when the latter has discharged 

 itself, frequently burst of themselves externally. In Paramecium 

 aurelia, &c., it is attached to the pellicula ; it also bursts externally 

 in Amoeba ; but in Vorticella it is attached to the buccal cavity, and 

 discharges itself close to the anal orifice, as in some Rotifera; in 

 Astasia it is close to the oral aperture and never disappears entirely, 

 even if it diminishes now and then in size. It is a distinct organ in 

 Vorticella and many of the Infusoria, perhaps so in all, and not a 

 mere accidental dilatation of the sarcode. The term " vesicula'' is 

 proposed for it instead of "contracting vesicle," from the incon- 

 venience of the latter in description. 



Nucleus, or Primary Organ. — This is a circular, moon-like body 

 (under the microscope), discoidal, and of a faint yellow colour. It 

 is contained in a transparent capsule, and fixed in the periphery of 

 the sarcode in the Rhizopoda, Astasia, Euglena, &c. In Ehrenberg's 

 class of Enterodelous Infusoria it is for the most part of a different 

 form. The presence of the capsule in Amoeba causes it to appear as 

 if surrounded by a narrow pellucid ring, but when the former becomes 

 globular, the nucleus is observed to be fixed to one part of it. After 

 a while the nucleus becomes granular and the capsule globular : it 

 then also enlarges and undergoes deduplicative subdivision, the seg- 

 ments of which do not fall into the capsule, but burst through it, and 

 appear in the form of a botryoidal mass on its periphery. When 

 the granules, which each segment (now become discoid or spherical) 

 contains, become endowed with locomotive power they separate, 

 and make their exit through the proper covering of the segment, 

 while in the body of the parent (which now perishes), or after the 

 segment has left its cavity. At first the nucleus appears to be a 

 presiding organ over the development of the cell, after the manner of 



