1869.] On the Rhizopodal Fauna of the Deep Sea. 59 



supramarginal lobules are connected by numerous bands of fibres, that the 

 ascending parietal gyri have central and callosal fibres entering their extre- 

 mities, the middle portion receiving comparatively few ; the first, however, 

 sometimes called the ascending frontal gyrus, seems to have numerous 

 fibres from the centres and C. callosum along its entire length. The 

 second frontal convolution sends bands of fibres obliquely to the two 

 others, and has fewer radiating fibres than they have. "When it is removed, 

 fibres can be traced transversely across the valley left from the first to the 

 third. 



A few additional particulars are given respecting the arrangement and 

 course of the fibres in the callosal and marginal gyri on the internal surface 

 of the hemisphere, and the contrast between the thalamus and C. striatum 

 as to structure and relations is pointed out, the thalamus sending large 

 masses of fibres in every direction, chiefly with the radiating crus, the 

 corpus striatum consisting of soft grey matter enclosed in fibrous planes 

 which arise in the comparatively small grey nuclei, and have apparently no 

 communication with the main body of the ganglion. The thalamus again 

 does not seem to receive terminating ascending fibres, while both divisions 

 of the crus give off numerous fibres, which are seen to end in the C. 

 striatum. 



The differences in naked-eye appearances indicate differences in the rela- 

 tions between cells and fibres in the two ganglia, the exact nature of which 

 can be ascertained only by the microscope. 



XXVI. " On the Rhizopodal Fauna of the Deep Sea." By William 

 B. Carpenter, M.D., V.P.R.S. Received June 17, 1869. 



(Abstract.) 



The Author commences by referring to the knowledge of the Rhizopo- 

 dal Fauna of the Deep Sea which has been gradually acquired by the 

 examination of specimens of the bottom brought up by the Sound- 

 ing-apparatus ; and states that whilst this method of investigation has 

 made known the vast extent and diffusion of Foraminiferal life at great 

 depths, — especially in the case of Glohigerina-mud, which has been proved 

 to cover a large part of the bottom of the North Atlantic Ocean, — it has 

 not added any new Generic types to those discoverable in comparatively shal- 

 low waters. With the exception of a few forms, which, like Globiyerina, 

 find their most congenial home, and attain their greatest development, at 

 great depths, the general rule has seemed to be that Foraminifera are pro- 

 gressively dwarfed in proportion to increase of depth, as they are by a 

 change from a warmer to a colder climate ; those which are brought up from 

 great depths in the Equatorial region bearing a much stronger resemblance 

 to those of the colder-temperate, or even of the Arctic seas, than to 

 the littoral forms of their own region. 



The Author then refers to the recent researches of Prof. Huxley upon 



