86 Mr. G. M. Dawson on Foraminifera 



Newfoundland, or to the sonth of Cape Breton, a change from 

 the gulf fauna is immediately detected. Polystomella striato- 

 punctataj there so common, becomes rare. Nonionina lahra- 

 dorica to a great extent ceases to appear, and Uvigerina pyg- 

 mcea and Cassidulinidse become more frequent. 



The &.Yen&.ceoi\s Li'tuola Jindens, D. & P. (1)*, Hippocrejnna 

 indivisa, D. & P. (2), Lituola cassis, D. & P. (3), are most plen- 

 tiful at depths less than 20 fathoms. Lituola scorpiuris (4) 

 goes down to the greatest dejjths in Gaspe Bay, and is yet 

 abundant at 10 fathoms, while the immense RTiabdopleura'^ (7) 

 only appears at about 20 fathoms, and continues from that 

 point increasing in numbers and size to the depth of 50 fathoms, 

 which is the greatest depth in Gaspe Bay, where alone it has 

 been found. 



The disti'ibution of these Foraminifera would tend, with 

 other facts, to show that these organisms, together with most 

 other marine animals of low organization, do not depend to 

 any great extent on the depth or intensity of daylight, but 

 almost entirely on the temperature of the water, as Dr. Car- 

 penter maintains in his account of his recent deep-sea dredging; 

 so that they Avould not give very satisfactory evidence of the 

 conditions of deposit of Postpliocene or other beds, unless 

 other facts were at disposal to show the depth, when the Fo- 

 raminifera would give valuable assistance with regard to the 

 climatic conditions at that depth. The quality of the bottom, 

 however, has much to do with the general fades of the Fora- 

 minifera, as with other animals ; for, as shown above, calm 

 water, with a bottom composed of fine sand and sediment, is par- 

 ticularly favourable to the arenaceous forms, though, even under 

 these conditions, they do not thrive in the very cold, deep water 

 (such as that below 100 fathoms) in the open gulf. A strong 

 cuiTcnt at once causes all sandy forms to disappear, mostly, 

 no doubt, from the want of the fine materials necessary for 

 their shells, and brings in a large preponderance of Planorbu- 

 linas, Lagenida3, &c. 



The arenaceous forms, with the exception of those which 

 are tubular, constitute a series parallel to the calcareous forms, 

 and the members of which graduate into one another. It 

 seems not improbable that the individuals of the same species 

 may assume either appearance. It does not appear, however, 

 that the same individual can present both forms at successive 

 periods. On the other hand, the sandy forms may really con- 

 stitute a distinct group parallel to the others. Sketches of 

 some interesting new forms are given. Dr. Parker has kindly 

 assisted in naming some of the arenaceous forms. There are 

 • The figures refer to the numbers of the Tvoodcuts. 



