436 



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



the preceding pages. It is also evident that some species were capable 

 of existing at a great variety of depth, for instance: — 



Platydia anomioides is recorded from 40 to 600 fathoms. 



Hhynchonella psittacea from 10 „ 690 „ 



Terebratula vitrea „ 5 „ 1,456 „ 



Discina Atlantica „ 600 „ 2,400 „ 



Terebratula Wyvilli „ 1,035 „ 2,600 „ 



The animal of the same species of Brachiopod is, moreover, capable 

 of existing at different depths without any observable modification 

 in shape and character. It has also been clearly ascertained that the 

 Brachiopoda, although widely distributed, are very much localised, 

 and usually occur in great numbers in their respective haunts. 



If we examine the nature of the sea bottom, from which the ' Chal- 

 lenger ' specimens were obtained, we find that they were dredged nine 

 times from sea bottoms composed of rock and clay, once from stones 

 and gravel, three times from sand, and eleven times from soft bottoms 

 composed of mud, globigerina, or grey ooze ; but as previously stated, 

 as a rule they prefer rocky bottoms and coral reefs. 



Out of the 30 or 31 species of Brachiopoda dredged during the 

 ' Challenger ' Expedition, ten or eleven appear to be undescribed, 



1. Terebratula Wyvilli, n. sp. 



This is a very interesting species of about 18 millimetres in length, 

 by 17 in width, and 9 in depth, is nearly as broad as long, semi-trans- 

 parent,* smooth, and thin. It has a wide concave depression in the 

 dorsal valve, and a fold in the ventral one with a small simple loop in 

 the interior of the dorsal valve. It bears much external resemblance 

 to several species of Waldheimia of the W. carinata group, but differs 

 from the forms of that group by the shape of its loop. It was dredged 

 at four stations, lat. 42° 41' S., long. 134"° 10' E., depth 2,600 fathoms ; 

 in lat. 33° 31' S., long. 74° 43' W., depth 2,160 fathoms ; lat. 42° 43' S., 

 long. '82° 11' W., depth 1,450 fathoms; a small example was also got 

 not far from Falkland Island, depth 1,035 fathoms. 



2. Terebratula Moseleyi, n. sp. 



The shell is broadly oval, semi-globose, and rather longer than wide, 

 white and smooth, loop short, simple ; length 23, breadth 21, depth 

 14 millims. 



Five examples were obtained all about the same size. It seems to 

 be a smaller species than T. vitrea and T. Cubensis, its nearest allies, 

 is less elongated and not as convex. It was dredged west of Kerguelen 

 Island, lat. 46° 47' S., long. 51° 37' E. ; depth 210 fathoms. 



3. Terebratulina Wyvilli^ n. sp. 



This is the most remarkable species of Brachiopod brought home 



