10 BED OP THE ATLANTIC. 



and Rotalia, the universal characteristic, with Lagena, Lituola, and numerous 

 Coccoliths and Coccospheres ! and many other varieties of forms not here 

 figured. 



Those from lesser depths present a marked contrast to the above ; they are 

 of a greater specific gravity, consisting chiefly of coarse grains of silex with 

 Diatoms, but few Foraminiferse, and those chiefly Globigerinse and Coccoliths, 

 for the most part water worn. 



Many Polycystina, of various beautiful and fantastic forms, such as Podocyrtis, 

 Astromma, Eucyrtidium, Lychnocaniurn, and numerous others, were also found, 

 and some are here attempted to be figured, but no adequate description can be 

 given, or idea formed, with pen or pencil, of such varied and exquisite forms. 



Some of these illustrations are selections from drawings which were made on 

 the first arrival of H.M.S. Gannet from her cruize in the Gulf Stream ; but 

 as those were intended only to give a very superficial and general idea of the 

 nature of the bottom at so great a depth, the present plates have been sub- 

 stituted. More time and care have been devoted to them many have been 

 subjected to the full powers of one of Smith and Beck's best binocular micro- 

 scopes many forms magnified with i and -^-powers, with shifting eye-pieces, 

 to 300 and 850 diameters with the ^-power, and to 900 and 1800 diameters with 

 the -|-power. 



To Dr. Moorhead, of Weymouth, whose beautiful microscope first revealed 

 these interesting forms to me, and enabled me to make my first series of 

 drawings, magnifying 252 specimens, I am very much indebted. 



And to George Bishop, Esq., of Twickenham, whose powerful microscope 

 shewed all the minute detail seen in the several series of sketches, I am 

 particularly indebted ; and if these few leaves should ever appear in print, I 

 avail myself of the opportunity of recording my best thanks. 



To the Rev. Eugene O'Meara, of Dublin, author of many interesting works 

 on Diatomaceso, who, from the beginning, took great interest in these deep-sea 

 creatures, I owe many thanks for having corrected much of the orthography 

 in these plates. 



Many instructive ideas suggest themselves from these gleanings in the Gulf 

 Stream this Mighty Ocean River! and the soundings collected from beneath 

 it. These latter are worthy of much thought and investigation. 



