Dr. G. C. Wallicli on the Coccosphere. 347 



the best explanation I liave as yet come across, though 

 even this has a weak point in it. It was, that the animals of 

 the Foraminifera probably employed the coccoliths^ which 

 abound in the mud, instead of sand or other particles for the 

 strengthening of their shells, as we know to be the habit of a 

 large number of the Foraminifera that live at the bottom of 

 the deep sea. But, although the sparse kind of tessellation 

 with large mineral particles here and there on the shell is un- 

 doubtedly characteristic of some species (as for example Pro- 

 teonina and Buliminia ; and, as I have elsewhere shown to be 

 the case in certain deep-sea Foraminifera as well as freshwater 

 testaceous Rhizopods, "the selective and adaptive power" 

 exhibited in the material and workmanship of the shells is 

 simply marvellous), in the shells now under notice the arrange- 

 ment of the coccoUths appears almost too like that observable 

 on the coccospheres to render it easily intelligible how the animal 

 of the Foraminifer could have so exactly "mimicked" it. 

 On the other hand, there is a piece of evidence which would 

 seem to support Mr. Carter's view of unicellular algal affinity 

 (supposing it to be extended to the coccosjphere) , namely, an ap- 

 pearance of " dehiscence " which presents itself not unfre- 

 quently in the large oblong coccospheres met with in tropical 

 seas, and so invariably occurs, at one end only, as to negative 

 the idea of its being accidental (See Plate XVII. fig. 4). 



Mr. Carter suggests that the " loose type " of coccosphere 

 described and figured by Prof. Huxley may " be a still more 

 developed form of the sporangium or coccosphere, perhaps 

 undergoing dehiscence" (loc. cit. p. 189). He will, however, 

 I know, pardon me saying that it is going too far ahead of 

 the evidence to assume that the coccosphere is a sporangium 

 at all; for if it be, out of the multitudes I have seen, none has 

 ever departed from the sporangial phase, either in those met 

 with at the top or at the bottom of the ocean. But a glance at 

 the ciu'ious object I have depicted (Plate XVII. fig. 18), which 

 I have repeatedly met with in some parts of Bengal, will at once 

 show that Unicellular Algee do undoubtedly assume a sporan- 

 gial condition in accordance with that which Mr. Carter must 

 have had in his mind's eye when he suggested that the cocco- 

 sphere might be a sporangium. My specimen is, I believe, 

 the sporangial condition of a branching stipitate form oi An- 

 kistrodesmus^ each of the kidney-shaped bodies being a frond. 



Figures 1 to 4 (see PlateXVII.) represent the only two species 

 of Coccosphere I have hitherto met with : — the spherical one 

 being the ubiquitous oceanic form, which I propose to call Coc- 

 cosphcera pelagica] the oblong species, which is not so common 

 by any means, being, so far as my experience goes, confined 



