Distrihution of Saccammina sphaBrica, etc. 8 



translucent and ^-^ mm. thick, distinctly enclosed another whicli 

 contained the sarcode-body, and which was naturally also a globular 

 hollow space. This latter was composed mainly of small sand-grains 

 which were glued together with a finely granulated grey-brown 

 cement of the colour which characterizes the adult sliell. Whilst 

 the outer surface, as already noted, is only moderately smootli, 

 and, moreover, sometimes interrupted by an out-jutting sand-grain 

 or small stone (Plate I, fig. 13), so the interior surface appears to be 

 from every point of view uniform and quite smooth. In the inside 

 of these sand-capsules, in some cases, a granular soft mass was 

 found which could be taken to have been altered Rhizopod proto 

 plasm coagulated by the action of the spirit in which the material 

 had been preserved. Generally the shells were empty." 



The confusion which has constantly obscured the history of 

 the two forms makes its appearance at this early date, for of the 

 six small and rather indefinite figures with which Schulze illus- 

 trated his new species, one at least (J, fig. d) unquestionably repre- 

 sents the species already named by M. Sars, while three other 

 figures (a, h, and e) are open to doubt and may represent either 

 abnormally regular specimens of Psammosplifera fusca, or speci- 

 mens of Saccammina spliserica viewed from a point from which the 

 characteristic aperture of that species is invisible. Two only of 

 Schulze's figures (c and /) represent undoubtedly, the form which has 

 since been figured and described as the typical Psammosphaera fusca. 

 An examination of the co- types of Psammosphaera fu>>ca mounted 

 by Schulze and preserved in the " Brady Collection," now in the 

 Museum of Comparative Anatomy at Cambridge, tends to confirm 

 our belief that Schulze failed to discriminate between the two 

 species. The specimens are mounted in fluid, in cells, and cannot 

 be examined with any great precision, but in their large size and 

 general appearance they resemble Saccammina sphserica more than 

 Psammosjjh^ra fusca. As, however, no aperture can be seen in 

 the present position of the specimens, their exact identity remains 

 doubtful. 



In 1883 Dr. Haeusler noted the occurrence of Psammospheera 

 fusca in a fossil condition, and (4) gave three good figures of the 

 form, pointing out that an identical organism was to be found in 

 the Bimammatus zone and in the Transvcr sarins zone of the 

 Jurassic, differing only from recent specimens in its relatively 

 small size (0 • 1 mm.) and in points attributable to chemical and 

 geological influences. 



In 1884 Brady in his report on the scientific results of the 

 Challenger Expedition (5) diagnosed the two species at some length, 

 in connexion with specimens obtained on that Expedition. His 

 figures leave little to be desired. They represent typical specimens 

 of either form, presenting all the marked characteristics which dif- 

 ferentiate the two species. But in his diagnostic descriptions of the 



B 2 



