44 SHALLOW- WATER FORAMINIFERA OF TORTUGAS REGION. 



has been assumed by most writers that the color of the test in certain 

 of the Rotahidae, for example in Discorbis, was due to the con- 

 tained protoplasm. I had supposed that the specimens with deep 

 color were specimens in the living condition when taken. Heron- 

 Allen makes a similar note (loc. rit., footnote, page 257) in speaking 

 of Tretomphalus bulloides as follows: 



"The color varies from pure white to a deep brown, owing to the contained 

 protoplasm, which is frequently as dark as in Discorbina mediterranensis 

 (d'Orbigny) and therefore of that group." 



In crushing specimens which had a series of dark-brown chambers 

 in the rotaliform portion, I found a thin, nearly transparent brown 

 lining that could be separated from the interior of these chambers, 

 after which they were white. This hning seemed structureless, 

 suggesting a chitinous character, and appeared to be the source of 

 the color in the chambers. The specimens had not been dried and 

 the hning was of uniform character and thickness, and could scarcely 

 have been dried protoplasm. It may be suggested that a similar 

 condition should be looked for in other colored Rotaliidse, especially 

 where the early chambers only are colored. 



When the "float-chamber" was removed the under side of the 

 rotaliform portion had the appearance shown in figure 3, very 

 different from even the small specimens of Cymbalopora poeyi. The 

 suggestion that Tretomphalus bulloides is a stage of Cymbalopora, or 

 of Planorbulina, or of Discorbis does not seem to hold in the Tortugas 

 region. All the pelagic specimens of Tretomphalus bulloides were 

 much smaller than those of Cymbalopora poeyi and had a different 

 shape and general character. The ventral side does resemble that 

 of Cymbalopora poeyi, but only in a general way. It may be that 

 these small forms are all megalospheric and are thus producing the 

 sexual zoospores for the formation of the microspheric generation, 

 but no specimens referable to the latter were found in the tow-nets 

 during my stay at the Tortugas. 



A peculiar character of the pores of the test was noted, as shown. 

 The early chambers have comparatively large pores, which in- 

 crease in numbers but decrease in size in the succeeding chambers 

 until in the ''balloon-chamber" they are very fine, except for the 

 large pores at the base. 



A preliminary study of abundant material of Tretomphalus bul- 

 loides from Samoa, collected by Dr. Alfred G. Mayor, seems to show 

 that a very different species of the genus is developed there and that 

 instead of Tretomphalus and its enlarged "balloon-chamber" being 

 a stage in several genera, as suggested by Heron-Allen, it seems 

 really to be a genus with several distinct species with definite dis- 

 tributions. This is further indicated by the second species, 

 Tretomphalus millettii (Heron- Allen, and Earland), which is known 

 from the Indo-Pacific. 



