OF SOUNDINGS. 13 



without the aid of a magnifier. It appears to exist only in the deep soundings, 

 and is particularly abundant in those marked G, No. 8, 89 fathoms. 



None of the species of Textulai-ia, which are so abundant in our tertiary marls, 

 have been found by me during the examination of these soundings. 



Genus Triloculina, D'Orb. Shell free, inequilateral, globular or com- 

 pressed, having the same form at all ages, formed of enveloping cells developed 

 on three opposite faces, so that three cells only are visible ; their cavity is sim- 

 ple* Aperture single, round or oval, placed alternately at one or the other end 

 of the longitudinal axis, and furnished with a more or less complicated tooth. 



Triloculina brongniartiana, (figs. 44, 45).^ Shell oblong, convex, a little gib- 

 bose with fine longitudinal stria?, obtuse posteriorly, acuminate and rostrate an- 

 teriorly, outline convex, not at all angular. Cells arcuate, gibbose, rounded 

 behind, gradually diminishing in diameter in front up to the anterior portion, 

 when they suddenly contract to form the slender prolongation for the apertui'e. 

 Aperture small, round, with a small simple obtuse tooth. 



This description of a species common in the West Indies, appears to suit in 

 most respects the species represented in figs. 44 and 45, which was found in No. 

 27, 10 fathoms. 



Genus Quinqueloculina, D'Orb. Shell free, inequilateral, globular or com- 

 pressed, rounded or angular, having the same form at all ages, formed of envelop- 

 ing cells developed on five opposite faces, so that five only are visible. Cavities 

 simple. Aperture single, with a simple or compound tooth. 



Quinqucloculina occidentalism Bail., figs. 46, 47, and 48. Shell elliptical com- 

 pressed, not angular, of a smooth and porcellaneous texture. Aperture moder- 

 ately large, with a simple robust tooth. 



Found in the soundings marked F, No. 27, 20 fathoms, and not uncommonly 

 in the sands along the Western shores of the Atlantic. 



OVA OF POLYTHALAMIA.? 



The minute globular bodies, represented highly magnified in fig. 49, are par- 

 ticularly abundant in the soundings No. 1, 90 fathoms, S. E. of Cape Henlopen. 

 They also occur, though less abundantly, in the other deep soundings ; they are 

 found most easily when a portion of the mud is diffused in water, for when 

 mounted in Canada balsam, their refractive power is so nearly that of the bal- 

 sam, that they become almost invisible. Their real nature is wholly unknown 

 to me, but from their occurrence with the Polythalamia, and their resemblance 

 in form and size to the globular bodies sometimes found in the fossil Polythala- 

 mia which have been supposed to be the fossil ova of these minute animals,* it 

 is not improbable that these may be the eggs in a recent state. 



*See the interesting memoir on the fossil remains of the soft parts of Foraminifera, by Dr. Mantell, 

 Phil. Trans., Part IV for 1846, and Silliman's Journ., vol. 5, p. 70, new series. 



