Dr. (Jr. C. Walllcli on the Coccospliere. • 345 



Although Prof. Huxley, in his first brief notice of the coc- 

 coliths (already referred to as having appeared in 1858) de- 

 scribed the " coccolith " as being somewhat like a single cell of 

 the plant Protococcus^'' he has nowhere asserted that it is a 

 cell. In his paper describing Bathyhius {' Quart. Journ. Micr. 

 Science,' Oct. 1868, p. 207) healludes to " a central coiyuscide,''^ 

 and says, " the7'e is in its centre a clear and transparent space^^ 

 adding that " sometimes, as Dr. Wallich has already observed, 

 the clear space is divided into two. This appears to occur 

 only in the largest of these bodies ; but I have never observed 

 any further subdivision of the clear centre, nor any tendency 

 to divide on the part of the body" itself." In the same paper 

 Prof. Huxley pointed out, for the first time, the double or shirt- 

 stud-Yike, figure of the " coccolitlis^'' a feature which I had 

 altogether overlooked, owing, doubtless, to my attention having 

 been chiefly directed towards the Coccospliere as a whole. 



Now every thing depends on a correct interpretation of what 

 Prof. Huxley describes as the central corpuscule and the clear 

 space at its centre. He says, " Suppose a couple of watch- 

 glasses, one rather smaller than the other ; turn the convex 

 side of the former to the concave side of the latter ; interpose 

 between the centre of the two a hollow spheroid of wax, and 

 press them together : these will represent the upper and lower 

 plates and the central corpuscule " (loc. cit. p. 207). This de- 

 scription is most closely borne out by Prof. Huxley's figures. 

 To facilitate my explanation, I have reproduced three of his 

 figures in the Plate which accompanies this paper — namely, 

 figs. 13 H, 14 H, and 15 H. It will be seen from these, 

 that if we apply his experimental illustration of the two 

 watch-glasses and the hollow spheroid of wax, where there is 

 one clear space in tlie centre of the central corpuscule, we 

 should have to employ either two hollow spheroids of wax, or 

 one spheroid with two cavities in it, to represent the coccolith 

 in which two central clear spaces occur ; and so on, whatever 

 the number of central clear spaces may be. To my mind this 

 does not by any means give a correct idea of the appearances ; 

 which, on the contrary, indicate that the central clear space or 

 spaces are either single or double perforations in the external 

 disk — its " markings," as it were — and nothing more. They 

 have, therefore, no physiological significance, and certainly do 

 not represent any thing that can be called a cell. See Plate 

 XVII. fig. 10, which gives a diagrammatic sectional view of a 

 coccolith. There is no evidence forthcoming, that I am 'aware 

 of, to show whether the stem of the stud {i.e. the intermediate 

 piece between the two disks), is or is not continuous with the 

 disks. As the appearance of concentric rings is constant, 



