ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 545 



Antarctic Bivalves.*— Edgar A. Smith reports on the collection of 

 Lamellibranchs made bj the ' Discovery.' It includes fourteen species,. 

 of which ten are new, e.g. Kellia simiilans, Philolrya Umoides, Limopsis 

 grandes, and a beautifully sculptured Lima. 



7- Gastropoda. 



Antarctic Pteropods.t— Sir C. Eliot reports on five species of 

 Pteropods collected by the ' Discovery,' viz. Limacina antarctica Wood- 

 ward, L. re.troversa (Fleming), Clio sulcata (Pfeffer), Clione antarctica 

 E. A. Smith, and Spongiohranchcm australis D'Orb. The two chief 

 forms are L. antarctica and C. antarctica, which seem to be distinct 

 from the coiTesponding northern species, though nearly related. The 

 characters which the Arctic and Antarctic forms of Limacina and Clione 

 present are compatible with any hypothesis which assumes that they are 

 derived one from the other, or from a common ancestor. One Antarctic 

 form, Clio sulcata, is closely allied to a cosmopolitan form, C.jyyramidata, 

 and may plausibly be considered as a special adaptation of it to 

 Antarctic life. Also if Limacina lesueuri is admitted to be merely a 

 variety of L. retroversa, then L. retroversa is cosmopolitan and bipolar. 

 Is it not probable, then, the author asks, that Clione antarctica and 

 G. limacina, plus some tropical forms of the genus, represent variations of 

 a once cosmopolitan species ? There is nothing unnatural in the idea that 

 such a species may have undergone similar but not identical changes in 

 the North and South Polar waters. 



Antarctic Nudibranchs.| — Sir Chas. Eliot reports on the 'Discovery' 

 collection of Nudibranchs, which includes 12 species, 10 new. He 

 establishes two new genera, Tritoniella, near Tritonia, but with a wide 

 dorsal margin bearing, instead of foliaceous tufts, simple unbranched 

 prominences, which have a few' lamellae on the under side, and GalvinellOr 

 near Gcdvina, 



Antarctic Chiton.§ — Edgar A. Smith describes an interesting chiton 

 {Chcetopleura miranda sp. n.) obtained by the ' Discovery.' Its colora- 

 tion is remarkable, the third and seventh valves being stained with red, 

 the rest being dirty whitish. The same form has been simultaneously 

 described by J. Thieie under the name Notochiton mirandus g. et sp. n. 

 This specimen was obtained by the German Deep-Sea Expedition from 

 Bouvet Island, which shows the wide distribution of the species. 



Antarctic Gastropods. || — Edgar A. Smith reports on the 'Discovery' 

 collection, which includes 26 species, 21 new. The collection does not 

 show any particular resemblance to the Arctic fauna, most of the genera 

 having a world-wide distribution. The general absence of colour is- 

 characteristic. The most striking forms are Trophon longstaffi and a 

 new genus Trichoconcha, with a flexible tough shell like a chestnut skin, 

 and a beautiful hairy periostracum. 



* National Antarctic Expedition, ii. (1907). Lamellibranchiata, 7 pp., 1 pi. 



t Op. cit., iii. No. 6 (1907) pp. 1-15 (2 pis.). 



J Op. cit., ii. (1907). MoUusca, IV., 28 pp., 1 pi. 



§ Tom. cit., 1 p., 1 pi. II Op. cit., iii. (1907). MoUusca, II., 12 pp., 1 pL 



