IG DK. T. DAVIDSON OX EECENT BRACHIOPODA. 



fathoms. Off coast of Chili (Valparaiso), along Avith Wald/ieimia TFi/villii -dnd Discimsca 

 atlantk-a. In lat. 42° 43' S., long. 82° 11' W., tlei^th 1450 fathoms. Off coast of 

 Patagonia. One small example from the net-weights, not far from Falkland Islands, at 

 a depth of 1035 fathoms. And, lastly, in lat. 35° 22' N., long 169° 58' E., depth 2900 

 fathoms, the greatest deptli at which any Brachiopod was ohtaiued by the ' Challenger ' 

 Expedition ; bottom-temperature l°-2 C. ; sea-bottom, red clay. 



Ohs. Liotlujris JFyvillii is one of the most interesting species of deep-sea Brachiopoda. 

 The shell is of such extreme thinness that it is almost transparent ; indeed the valves, when 

 separated, are really so, and the muscular impressions may be seen through its transparency. 

 I separated the valves of a specimen in order to be able to study the auimal and its loop. 

 The latter, which I was much surprised to find short, is exactly similar to that oiLiothyris 

 vitrea, notwithstanding the outward Waldheimia-Yv^e appearance of the shell. It bears 

 also much resemblance to several species of the last-named genus occurring in the Jurassic 

 and Cretaceous formations. We meet with but few recent species with such a thin 

 shell ; but among others may be named the widespread Discinisca atlaiitica, King, 

 Atretia gnomon, Jeffreys, JP'aldheimia or Macandrevia tenera, Jeffreys, RhijncUonella 

 lucida, Gould, and one or two others. 



In external shape and character of loop, Liothyrts JFyvillii also strongly resembles 

 the Terebratnla nucleata of Schlotheim. Zittel's figure 644, on page 700 of his 

 ' Handbuch der Paliiontologie,' 1880, seems as if drawn from a specimen of the recent 

 L. IJ'yvilUi. Eor T. nucleata Douville proposes a genus Glossothyris ; but this I am 

 unable to admit or adopt. 



Fncertain Species. 



9. LiOTHYRis CEUNiCA, Crosse, sp. (Plate I. fig. 19.) 



Terebratnla cernica, Crosse, Journal de Conchyliologie, vol. xxi. p. 285, and vol.xxii. p. 75, pi. i. fig. 3, 

 1873. 



Shell longitudinally oval, somewhat pear-shaped, longer than wide, broadest anteriorly, 

 tapering posteriorly. Valves uniformly convex and globose, lateral margins rounded and 

 flexuous. Surface smooth, white, semitransparent and somewhat vitreous. Beak not 

 much produced, incurved and truncated by a small circular foramen, separated from the 

 hinge-line by a deltidium in two pieces. Loop not known, in all probability short and 

 simple, as in L. vitrea. Length 1 inch 4 lines, breadth 1 inch 1 line. 



Sab. Off Mauritius Island (Lienard). 



Ohs. Mr. Crosse, in his description, says that T. cernica, from the lateral compression 

 of its dorsal valve, possesses affinities with T. ura, Broderip, but that it is less elongated 

 and more globose, and approaches T. vitrea and, even more closely, T. ciibensis of Pourtales. 

 I have never seen the single example of the shell under description ; but from inquiries 

 I made in the Island of Mauritius, Mr. V. Ptobillard has informed me that it has not 

 been dredged, but was found in the stomach of a fish taken at 80 fathoms depth, that it 

 is the only .specimen existing, and that there is but little chance of finding it again. lie 

 adds that he does not know of any other species of Brachiopod from the Avaters of 



