62 THE VOYAGE OF H.M.S CHALLENGER. 



none of the numerous examples brought back by the Challenger Expedition exceeded the 

 dimensions abeady given. The manner in which the Lingulce slide their valves upon 

 one another has been admirably described by Professors Semper, E. Morse, and W. King. 

 Some of the Philippine specimens of Lingula anatina approach very nearly in shape, and 

 vivid verdigris-green brilliancy of colour to Lingula ovalis, of Reeve, from Honolulu, one 

 of the Sandwich islands. I may, however, mention that the name ovalis cannot be made 

 use of for the recent species, as it had been given many years previously to a fossil one. 

 I, therefore, propose to substitute the specific designation of Lingula reevii for the recent 

 species. 



Discina, Lamarck. 



Disoina atlantica, King (PL IV. figs. 17, 18). 



Discina atlantica, King, Proc. Nat. Hist. Soc. of Dublin, vol. v. p. 170-173, 1868 ; Dav., Brit. Foss. 



Brach., vol. iv. sup., p. 2, pi. i. fig. 11, 1874. 

 Discinisca (?) atlantica, Dall, Cat. Eecent Brach., Proc. Phil. Acad. Nat. Sciences, p. 177, July 1873. 

 Discina atlantica, J. Gwyn Jeffreys, Annals and Mag. of Nat. Hist., p. 252, 1876, and Proc. Zool. 



Soc, 1878, "Porcupine" Expedition, 1869. Station 19a, 1366 fathoms. 



Shell very small, slightly longitudinally oval, broadest anteriorly, sometimes marginally 

 almost cii'cular. Shell very thin, semitransparent, corneous, light yellowish-brown, marked 

 with numerous concentric lines, or ridges of growth. Dorsal or upper valve oonical ; 

 vertex almost central, or situated at about one-third of the length of the valve from the 

 posterior margin ; ventral valve flat, exceedingly thin. Length 3, breadth 2f mm. 



Habitat. — This species was not known previous to 1862. Since then it has been 

 dredged in no less than eight separate and widely-spread localities. It appears to be 

 a very abundant shell, but occurs only at very great depths. It was obtained at seven 

 or eight difi'erent localities by the Challenger Expedition : — 



Station 106 (PL IV., fig. 17,a,b,c), August 25, 1873, lat. 1° 47' N., long. 24° 26' W. 

 Bottom temperature, 1°"8 C. Sea bottom, globigerina ooze. Three examples attached 

 to Limopsis aurita, Brocchi, associated with one example of Megerlia (?) incerta, Dav. 

 Depth, 1850 fathoms. This station is situated between the Cape Verde Islands or Sierra 

 Leone (Africa), and Fernando de Noronha (South America). 



Station 194, September 29, 1874, lat. 4° 33' S., long. 120° 58' E. Depth from 200 

 fathoms to 360 fathoms. Sea bottom, volcanic detritus. 



Station 237 (PL IV. fig. 18), June 17, 1875, lat. 34° 37' N., long. 140° 32' E. 

 Depth, 1875 fathoms. Bottom temperature, 1°'7 C. Sea bottom, mud. Some examples 

 of the upper valve were got in washing the dredge, along Tsdth one specimen of Terehratula 

 dalli. 



Station 246, July 2, 1875, lat. 36° 10' N., long. 178° 0' E. Depth, 2050 fathoms. 



