and Reproductive Phenomena of the Amoeban Rhizopods. 457 



specimens, however, are built up partly of these pellets and 

 partjy of sandy particles combined; whilst others appear to 

 have one portion of the test built entirely of pellets and the 

 other entirely of sandy particles. But the polariscope enables 

 us to perceive that in nearly every specimen the basal layer of 

 chitinous matter is strengthened by delicate films of mica, and 

 that the external wall, whether formed of coarse sandy particles 

 or pellets, is superimposed upon it. This structure of the test is 

 to be traced in the curious variety of Difflugia proteiformis alluded 

 to by me in the ' Annals ' for June (p. 451, pi. 10. fig. 12) as being 

 remarkable on account of the development of a septum between 

 the main cavity of the test and its broad tubular neck, which 

 causes it to resemble the two earliest chambers of the shell in 

 Miliola. But one and all of these modifications, as before stated, 

 are manifestly confined to the test, and in no appreciable manner 

 associated with equivalent difi'erences in the animal mass. 



During the past summer and autumn, the same forms have 

 been met with by me very generally in boggy pools — merging, 

 on the one hand, into the " pyriform " variety, both with and 

 without the little apical appendage of the test, and, on the 

 other, passing into the equally common subglobular variety. 



I have now to notice two still more aberrant forms recently 

 obtained from the Hampstead pools. Of the first of these, only 

 a single specimen has as yet presented itself from that locality. 

 I had previously, however, met with one or two nearly similar 

 specimens in a boggy streamlet on the west coast of Greenland*. 

 Owing to the extraordinary transparency of the Hampstead 

 specimen, which was still alive when examined under the micro- 

 scope, it afforded a good opportunity for the detection of any 

 novel characters within the sarcode-mass, had these existed. 

 The pseudopodia were finely granular, free from incepted matters, 

 and more or less cylindrical and lobose as in the ordinary 

 Diffiugice ; the sarcode-substance charged with variously coloured 

 food-particles j the nucleus spherical, apparently homogeneous 

 throughout, and sustained in the usual hyaline cavity towards 

 the fundus of the test; whilst the contractile vesicle was single, 

 and, although partaking in the movements within the test 

 dependent on the protrusion and retraction of the pseudopodial 

 processes, returned to discharge itself, as in Amoeba, at the 

 posterior portion of the body. So that the characters are iden- 

 tical with those of Diffiugia proteiformis, although, owing to the 

 irregular structure of the test in that species, they are observable 

 with much greater difficulty, and hardly ever simultaneously as 

 in the present example. 



* A figure of the Greeuland Diffiugia may be seen on reference to Part I, 

 of 'The North Atlantic Sea-bed' (pi 4. fig. 1/). 



Ann. ^ Mag. N. Hist. Ser. 3. Vol. xii. 30 



