290 Royal Society. 



The family Lagenida was represented not merely by its smaller 

 forms, but also by a large and beautiful living Cristellaria, that 

 closely corresponds with one of the forms described by Fichtel and 

 Moll from the Siennese Tertiaries, whilst even exceeding it in dimen- 

 sions. 



These results conclusively show that reduction in the size of 

 Foraminifera cannot be attributed to increase of pressure, since the 

 examples of Cornuspira, Biloculina, and Cristellaria found at depths 

 exceeding 500 fathoms were far larger than any that are known to 

 exist in the shallower waters of the colder temperate zone. But as 

 these all occurred in the warm area, whose bottom-temperature in- 

 dicates a movement of water from the Equatorial towards the Polar 

 region, it is probable that their size is related to the temperature of 

 their habitat, which is found to be in like relation to the general 

 character of the fauna of which they formed part. On the other 

 hand, as we now know that the climate of the deepest parts of the 

 ocean- bottom, even in Equatorial regions, has often (if not uni- 

 versally) Arctic coldness, the dwarfing of the abyssal Foraminifera 

 of those regions is fully accounted for on the same principle. 



Besides these examples of new or remarkable forms of Foramini- 

 fera, the ' Lightning' dredgings yielded some peculiar bodies, the 

 examination of which would seem to throw light upon the obscure 

 question of the mode of reproduction in this group. One set of 

 these are cysts, of various shapes and sizes, composed of sand-grains 

 loosely aggregated (as in the tests o( Lituola and Astrorhiza), which, 

 when broken open, are found to be filled with aggregations of mi- 

 nute yellow spherules, not enclosed in any distinct envelope. These 

 are supposed by the author to be reproductive gemmules formed by 

 the segmentation of the sarcodic body of a Rhizopod, in the same 

 manner as " zoospores " are formed in Protophytes by the segmenta- 

 tion of their eudochrome. Of such segmentation he formerly 

 described indications in the sarcodic body of Orbitolites ; and cor- 

 responding phenomena have been witnessed by Prof, Max Schulze. 

 But in another set of cysts, of similar materials but of firmer struc- 

 ture, bodies are found having all the characters of ova, with embryos 

 in various stages of development. In none of these, however, does 

 the embryo present characters sufficiently distinctive to enable its 

 nature to be determined ; and the hypothesis of the Foraminiferal 

 origin of these bodies chiefly rests upon the conformity in the struc- 

 ture of the wall of the cysts with that of the tests of Lituola and 

 Astrorhiza, and upon the improbability that such cysts should have 

 been constructed by animals of any higher type. 



