Furaminifcia. 1^7 



1872; and wheal tell you tliat one of these old authors, thus 

 treated, was Ehrenberg, you Avill he impressed with the patience 

 and labour of this work. 



It is incumbent on all who attempt to determine new species 

 to refer most carefully to previously published papers, and this, 

 formidable task as it is, has been rendered comparatively easy by 

 the bibliography appended to Brady's ' Challenger ' Report. lu 

 the course of the past three years I have made it my business to 

 refer to and index every figure in the known papers, and have 

 acquired the painful Jaiowledge that over 50,000 forms have 

 already been figured and described. 



The great majority of the Foraminifera live at the sea-bottom, 

 at moderate depths ; those living at the surface are nearly, if not 

 quite, confined to one family, the Globineriniihr, and occur in 

 relative abundance as follows : — Globhjerina, OrhuUna, Htisteri- 

 ijerbto, Pullenia, SpJurroidiiut, and Pulvinulina, the few other 

 "genera being of rare occurrence. Nearly all Foraminifera have 

 a wide geographical range, and seem to thrive at varying depths, 

 though depth usually makes a difference in shell-thickness. 

 According to the ' Challenger ' Eeport, by far the richest gather- 

 ing was obtained from a depth of 390 fathoms. The richest 

 locahty of the ' Challenger ' was Torres Strait, the warm shallow 

 waters of coral seas being especially rich and varied in their 

 minute fauna. 



The geological range is remarkably persistent. Lai/nia occurs 

 apparently the same as those of to-day, in Silurian Shales. The 

 Foraminiferal fauna of carboniferous times was probably peculiar, 

 though some well known recent forms occur; in Permian and 

 Triassic times the family of XodusaruKr, amongst others, existed 

 much the same as they do to-day. The Jurassic period was 

 extremely rich; thousands of "species" have been described 

 from European deposits. The Cretaceous forms are well known 

 to you through the labours of your member, the Eev. George 

 Bailey, and at the word luuiimulite everyone remembers the vast 

 importance of the Foraminifera in Tertiary times. 



^Vith regard to the variation of the test, in the diagrams on the 

 Avail I have endeavoured to trace the variations of form and orna- 

 ment in a simple Xodosaria. In a large collection of specimens 

 we can see the most perfect gradation from a smooth, unorna- 

 mented, single-chambered shell {Laijena), through all the vagaries 

 of dots, spines, ribs (either broken or continuous), and other far 

 more complex ornaments; and from a single-chambered shell 

 through the uodosarian (straight), deutaline (curved), cristell- 

 arian (partly or wholly coiled), to the most perfect spiral form, 

 either compressed or globulous ; and we cannot say this or that 

 is even a permanent variety. Taken separately, and for purposes 

 of classification, it is, as was said before, extremely useful to 



