430 



Mr. T. Davidson. On Brachiopoda. [May 23, 



1859, Professor E. Suess recapitulates all the then known data respecting 

 the geographical distribution and depths at which Brachiopoda live ; 

 since then, our knowledge has been very considerably extended ; and 

 it has become evident from direct observation that the Brachiopoda are 

 widely but sparingly distributed over the depths of the sea, though 

 of course they are more numerous both in species and individuals at 

 depths of less than 500 fathoms. They are much localised, and prefer 

 rocky, stony, and coralline sea bottoms, to soft or muddy ones. 



The entire collection of Brachiopoda brought home by the £ Chal- 

 lenger ' Expedition, numbering several hundred specimens, was placed 

 in my hands by Sir Wyville Thomson, on the 11th of August, 1877. 

 The specimens were in an excellent state of preservation, and had 

 been put into bottles of spirits, with a correct indication of the sta- 

 tions, latitude, longitude, depth, bottom-temperature, and the nature 

 of the sea-bed whence they had been obtained. Thus, reliable and 

 invaluable data accompanied each specimen, which I have in every 

 instance reproduced in the pages relating to this Expedition. Some- 

 times but one specimen had been dredged at a station, while at other 

 times two or more species or specimens w-ere brought to the surface. 

 It must, however, be noted that, in addition to the 361 dredging 

 stations included in the printed instructions, the naturalists of the 

 ' Challenger ' dredged very often in shallow water. 



We learn from the "list of observing stations," recorded during 

 the voyage of 68,890 miles, that there were 354 of such stations, at 

 most of which " a fair sample of the bottom fauna was collected by 

 means of the dredge or trawl." But Brachiopoda do not appear to 

 have been obtained more than thirty times. Although the number of 

 specimens was large, they represent 28 or 29 species only. The 

 greatest depth at which any living Brachiopod was obtained was 

 2,600 fathoms, the greatest depth dredged being, on one occasion, 

 4,575 fathoms. 



The ranges of depth at which the ' Challenger ' species of Brachi- 

 opoda occurred, were as follows : — 



Shore or low water 



to 10 fathoms. 



Waldheimia flavescens. Lamark. 





u 



Kraussina Laruarckiana. Davidson, 







Lingala anatina. Lam. 







Megerlia sanguinea. Chemnitz. 



5 to 



15 fms. 



Magasella flexuosa. King. 



25 „ 



30 „ 



Terebratella dorsata. Gmelin. 



38 „ 



49 „ 



Terebratulina cancellata. Koch. 



49 





Discina stella. Gould. 



51 „ 



150 „ 



Terebratulina caput-serpentis, var. septentrionali? 



70 „ 



75 ' „ 



Megerlia truncata. Linne. 



70 ., 



75 „ 



Argiope decollata. Chemn. 



82 



j> 



Terebratulina sp. (?) Philippines. 



Couthovy. 



