COCCOLITH8 AND COCCOSPHERES 



747 



Many testaceous amaibans have been recently discovered, whicli 

 form tests of remarkable regularity and sometimes of singular 

 beauty ; and it is difficult to determine, in many cases, whether the 

 minute plates of which they are composed have been formed by 

 exudation from their own bodies or have been picked up from the 

 surface over which the animals crawl. There can be no doubt of 

 this kind, however, in regard to the Qiiadrula symmetrica repre- 

 sented in fig. 580 ; the sarcode-body is here encased in a pear-shaped 

 test, of glassy transparence, made up of a great number of square 

 plates which touch each other by their edges. The sarcode-body 

 does not usually fill the test, the intervening space being occupied 

 by a clear liquid, and traversed by bands of protoplasm. In the 

 posterior part of the body is seen a large clear spherical nucleus, 

 with a distinct dark iiucleo- 

 lus ; and in front of this are 

 contractile vesicles, usually 

 two in number. 1 



CoccolitJis and Cocco- 

 spheres. This would seem 

 the most appropriate place 

 for the description of certain 

 peculiar little bodies found 

 very extensively diffused over 

 the deep-sea bottom, espe- 

 cially abounding in the Olo- 

 bigerina-mud, which may be 

 considered as chalk in process 

 of formation. It was in the 

 specimens of this mud 

 brought up by the ' Cyclops ' 

 soundings in 1857 that Pro- 

 fessor Huxley first found 

 the Coccoliths (fig. 581, l, 2) 

 which Dr. Wallich in 1860 

 found aggregated in the 

 spherical masses which he 

 designated as * coccospheres ' 

 (3). Regarding the gelati- 

 nous matrix in which they 

 were imbedded as a new type of the Monerozoa described by Haeckel, 

 having the condition of an indefinitely extended plasmodium, Pro- 

 fessor Huxley proposed to designate it by the name Bathybiiis, 

 indicative of its habitat in the depths of the sea ; and this idea was 

 accepted by Haeckel, whose representation of a living specimen of 

 Bamybiux, with imbedded coccoliths, is given in fig. 581, 3. The 

 observations made in the * Challenger ' Expedition, however, have 

 not confirmed this view ; the supposed Bathybius being a gelatinous 



1 See especially the admirable work of Professor Leidy on the fresh-water 

 rhizopods of the United States, 1880. It is to be regretted that its able author's time 

 and opportunities did not permit him to follow out the life-histories of the many 

 interesting forms whicli he has described and figured. 



FIG. 580. Qnadnda symmetrica, with 

 extended pseudopodia. 



