406 M. N. Lieberkiihn on the Development of 



a low magnifying power, two different layers of the substance 

 are distinguishable, — the uppermost possessing a low refractive 

 power, about equal to that of the ordinary sponge- cells, the 

 inner globular mass being highly refractive, almost like aggre- 

 gations of fat. When these are compressed by a glass-cover, 

 they become resolved into two kinds of cell -formations, both of 

 which are of about the size of the sponge-cells. The innermost, 

 which belongs to that portion which refracts the light most 

 strongly, adhere firmly together, and consist of a sarcoid mass, 

 in which tolerably large fat -like granules are densely interspersed. 

 When isolated, they exhibit motions resembling those of the 

 sponge-cells ; they emit processes into which the granules enter, 

 and again retract them. When forming a larger aggregation, 

 this resembles a lump of fat which begins to fuse, and emits 

 the liquid in separate strise in all directions. When suitable 

 pressure is made upon the mass, the original separate pieces are 

 distinguishable, but of the most variable forms. I was unable 

 to find in them the delicate transparent coat which surrounds 

 the white gemmules above described. In its place was found 

 only a layer of firmly cohering cell-like globules, some of which 

 resembled the sponge-cells in the arrangement of the granules 

 and the nucleolus, whilst the others enclosed amphidisks. Some 

 of the enclosed amphidisks had exactly the same form as those 

 usually surrounding the gemmules ; each bounding by the peri- 

 phery of its disk a circular portion of the interior of the shell of 

 the globule, which it encloses. In others the two disks were 

 not present, but a slender rod with slightly capitate ends existed 

 in the interior of the cell-like formation ; in others again, a row 

 of extremely slender setae radiated at right angles from the knob 

 of the rod. If these setae were broader and the stalk thicker, 

 the form would be that of the ordinary amphidisk. The outlines 

 of the cellular body furnished with an amphidisk are as sharp 

 and distinct as in the sponge-cells, but I could not find a 

 nucleus in them ; sometimes they contained some fat-granules. 

 Among the white gemmules were some with amphidisks enclosed 

 in vesicles situated upon their transparent envelope together 

 with free amphidisks. There can be no doubt that the pre- 

 viously described bodies are imperfectly developed gemmules. 

 Sometimes firmly connected whitish aggregations of sponge- 

 cells are found with them, of the same size and of a spheroidal 

 form. They are also obtained on dissecting a suitable portion 

 of sponge ; but usually the cells separate in this operation. 



I am not acquainted with similar facts in the case of the 

 sponges with smooth gemmules; neither have I hitherto met 

 with the smooth gemmules and those surrounded with amphi- 

 disks simultaneously in the same sponge. Both forms occur at 



