5<D CALIFORNIA ACADEMY OF SCIENCES. [ 3 d Ser., 



astrosphere lies very nearly in the position which we should 

 expect to find occupied by the archosome of the ovum. 

 Occasionally amoebse were found which were not in the act 

 of puncturing the ova; while in a few instances a single 

 amoeba was seen which had two points, each entering the 

 body of an adjacent ovum. 



As to the structure of the amoeba, Dr. Wheeler says, 

 "Each contained, besides a number of deeply staining ir- 

 regular granules, a pale round body, which I hesitate to in- 

 terpret as a nucleus, although it is certainly remarkable that 

 no other structure comparable to a nucleus could be found 

 in these amoeboid organisms, when they had been treated 

 with such an excellent nuclear stain as Heidenhain's iron 

 hematoxylin." I think that the absence of a nucleus indi- 

 cates that this body is not an amoeba, but something entirely 

 different; and the question now arises, must we not in this 

 so called amoeba recognize a free and independent archo- 

 some? The pale round body would then be interpreted 

 as a somosphere, and the irregular, deep-staining bodies 

 as centrosomes. An objection to this interpretation of the 

 dark, irregular granules might be made on account of their 

 position, situated as they are outside of the somosphere; but 

 this may be only a temporary position such as occurs also 

 in the plasmocyte, where the centrosomes now and then are 

 found outside of the somosphere, being free in the centro- 

 sphere. In the ova figured by Dr. Wheeler we find no 

 trace of any other archosome, but are told that the cyto- 

 plasm of the ova attacked by the amoeba contained large 

 granules which are larger and more numerous than those 

 which occur in the normal ovum at about the same stage. 

 These granules take up the haematoxylin with avidity. 

 Judging from the figures (Taf. 10, fig. 23, and Taf. 12, fig. 

 56) these granules in the ova are exactly similar to those in 

 the resting amoeba (fig. 56). In the entering amoeba these 

 granules as well as the pale round body are absent. It ap- 

 pears to me as if the pale round body, or somosphere, and 

 the granules, or centrosomes, had been injected into the 

 ovum by the free archosome. If this interpretation of the 



