DALL : MOLLUSCA AND BRACHIOPODA. 409 



Lima martlali Mabille et Rochebrune, Miss, du Cap Horn, Moll. , 1889, p. H. 124 ; 



Orange Harbor. 

 Lima (Limatula) pyrjinaea Smith, Chall. Rep., Lamell., 1885, p. 292. 



U. S. S. " Albatross," statiou 2777, Magellau Straits, in 20 fathoms, gravel ; 

 U. S. N. Mus. 9G,192; also at station 2778, in 61 fathoms, bottom temperature 

 47°. 9 P. Kergueleu Island, Smith ; South Orkuevs, Scottish Antarctic 

 Expedition? 



From the material available it seems that there are two species of Limatula in. 

 the Magellanic region, one of which was described as above indicated, by Philippi, 

 as having smooth radial ribs and the submargins without radial sculpture. 



One form, which I identify as pygmaea, has the smooth submargins large, and 

 extending nearly to the ventral border, without any radial sculpture upon them 

 whatever, and with the concentric sculpture of the disk confined to incremental 

 lines. The number of ril)s visible at the ventral margin does not exceed fifteen. 

 In neither of the species is there any medial sulcus. The very young show a dis- 

 tinct though minute taxodont provinculum, but the adult does not show the 

 hinge denticulatious of Limaea; although the general form and sculpture recalls 

 Limaea rather than the Limatula of the Northern hemisphere. 



Lima (Limatula) falklandica a. Adams. 



Limatula falklandica A. Adams, V. Z. S. Lond., 1863, p. 509. 



? Lima (Limatula) hodgsoni E. A. Smith, Nat. Antarct. Exp., Nat. Hist., 1907, 2, 

 Moll., p. 6, pi. 3, fig. 8. 



U. S. S. " Albatross," statiou 27S1, off the coast of Southern Chile, or West- 

 ern Patagonia, in 348 fathoms, mud, bottom temperature 49°.9 F. U. S. N. 

 Mus. 96,930. Also at stations 278:}, 27S4, and 27S7, in 61 to 194 fathoms, mud, 

 temperatures 48° to 54° F. Falkland Islands, A. Adams; South Orkneys, 

 Scottish Antarctic Expedition. 



This species, of which a good many specimens were collected, differs from 

 L- pygmaea Philippi, by having short and very small, smooth submargins, and in 

 having the radial ribs smaller, much more numerous, and obscurely divided into 

 three areas ; the median with about fifteen strong ribs ; an anterior with about 

 eleven gradually much smaller ribs ; and a posterior with about fourteen similar 

 ribs, gradually becoming obscure. All these ribs are elegantly sculptured by 

 small concentric, regularly spaced lamellae, wbich in crossing the ribs rise to 

 small vaulted scales exactly as figured by Smith for L. hodgsoni, as above cited 

 (fig. 8b). In some cases the scales are closer tlian in others, but this seemed the 

 only material variation. I am not sure that L. hodgsoni is specifically identical 

 with L.fidklandica, since the former is more than twice as large as the latter, but 

 the beautiful figure of the former given by Smith seems identical in every other 

 respect with our shells. I sc\wn\it falklandica from pgymaea + martiali, because 

 A. Adams especially mentions the concentric sculpture, while Philippi and Mabille 

 declare their shells to have " smooth " ribs. 



