THK DEPOSITS OF THE SEA-BOTTOM. 



83 



tioned. By this time, also, more light begins to be thrown over the origin of the Coccoliths, when 

 the discovery is made by Harting, that from an albuminous solution of carbonic ammonia bodies 

 resembling Coccoliths may be precipitated by chloride of calcium, and when, in 1889, it is pointed out 

 by Steinmauu 1 ) that such a precipitation may be made with albumen alone and chloride of calcium 

 or sulphuric lime, and when he from this fact draws the further conclusion that the calcareous shells 

 of all marine animals are made by such a process, while the animals that have no such shells, still 

 in the skin get formed numerous calcareous grains, which are removed by the moulting of the skin. 

 In the Paleontology by Steinmann and Doderlein, 1890, it is decidedly maintained that organic action 

 has been cooperating to the formation of the Coccoliths, and that consequently all marine lime stones 

 are to be regarded as fossils. Murray, in the report of the Challenger-Expedition, 1891, still main- 

 tains that the Coccospheres must be taken to be Algae. He denies their existence in the arctic regions, 

 a supposition, which, as will be shown in the following, does not hold good with regard to the terri- 

 tory treated of here. By Murray and several other authors the Coccoliths are often drawn with a 

 transverse partition through the central part; unfortunately I have not succeeded in discovering such 

 a partition. 



The Coccoliths are small, disk-shaped bodies; they are elliptical 

 when seen from the flat side; their size and the form of the ellipse is al- 

 most exactly the same in all of them; on an average the major axis mea- 

 sures ii//, the minor axis 9//. On the outside an everywhere equally broad 

 plate is found, which may be taken to correspond to the grain ring -f- 



outer ring of Haeckel; as I am not, however, quite sure of the correctness of this supposition, I shall 

 prefer to call this plate the marginal plate, a. Inside of this plate we find an elliptic ring per- 

 haps identical with the marrow ring of Haeckel; it may perhaps, be most properly designated the 

 central ring, b, and is in every respect the most interesting and most characteristic part of the 

 Coccolith; its outer circumference is generally S'/z// for the major axis, 372/* for the minor one. The 

 thickness of the central ring is a little more than 1 fi while that of the marginal plate is about 3//. 

 Innermost is found an elliptic sphere of dimensions about i'/ 4 ft by 23/ 4 p probably corresponding to 

 the central grain -(- the marrow sphere; I shall call it the central sphere, c. In an optic trans- 

 verse section the Coccolith appears as a curved disk, a consequence of its original position on the 

 outside of the Coccosphere. The central sphere appears as a very marked hollow on the outside, while 

 the central ring is formed by the thick margin of this hollow; on the inside the surface of the Coc- 

 colith is rather irregular, as it is torn from the Coccosphere; the outer part of the marginal plate, 

 however, has evidently not been firmly united with the Coccosphere, as we find in most cases in the 

 middle of the inside of the marginal plate, a distinctly projecting part, d, which seems to be the spot 

 where the surface of the Coccosphere has been broken off from the Coccolith. This same part may 

 be observed on a Coccolith seen from the flat, inner side where sometimes a very faint elliptic line 

 may be distinguished inside of the outer margin and parallel to this; this line, however, cannot well 



') S. Steinmann; Ueber Schalen- und Kalksteinbildung. Berichte der naturf. Gesellschaft zu Freiburg i B.; IV 

 Bd., 1889. 



