48 NATURAL SCIENCE. Jan.. 



Indies to the Gulf of Gascogny. It occurs off the East African coast, 

 on the shores of the Soudan, and also in the latitudes of the Azores, 

 another prolific region, yielding twelve species of Brachiopoda, of 

 which four are also common to the West Indies, and eleven to 

 European seas. A species dredged off the Portuguese coast, and 

 named Terehyatula sub-qtiadrata by Gwyn Jeff"reys, is now regarded by 

 Fischer and CEhlert as very closely allied to Dyscolia wyvillii, and the 

 same authorities recognise Terebraiula (D.) gniscardiana from the Sicilian 

 Pliocene as an ancestral form of this interesting family Dyscoliidae. 

 The authors concur with Davidson in regarding the T. septentrionalis 

 couthou}', which is larger and more rounded than the elongated and 

 sub-pentagonal T. capnt-serpcntis, as a distinct species. They note, how- 

 ever, the occurrence of the varietal form they have named T. germana, 

 from the Cape de Verde islands, and suspect it to be allied to the 

 examples of so-called T. septentrionalis, recorded from the South 

 Atlantic (Cape of Good Hope), the Indian Ocean, and Prince 

 Edward's Island (5). 



Sixteen deep-water species were obtained during the " Talisman " 

 and " Travailleur " expeditions, three of which, Rhynchonella cornea, 

 Eucalathis tuherata, and E. ergastlca, were previously little known (2). 

 Thirteen of them, according to Messrs. Fischer and CEhlert, occur in 

 a fossil condition in the Pliocene marine deposits of Sicily and 

 Calabria. These species are either absolutely identical, or at least 

 exhibit such slender differences as permit their describers, in calling 

 them by dififerent names, to indicate a common origin. The Zanclean 

 Sands of South Italy yield an assemblage of fossil forms which 

 recalls the abyssal fauna of the marine Lusitanian province. We 

 learn (2) that three species, R. sicula, Dyscolia gniscardiana, and 

 Mnhlfcldtla (Megerlla) grannlata, have become extinct in the Mediter- 

 ranean, while such closely allied forms as R. cornea, D. wyvillii, and 

 M. echlnata continue to be perpetuated in the Atlantic Ocean. Three 

 other species found in the Pliocene of South Italy, MageUania pelorltana, 

 M. euthyra, and that widespread and interesting species Liothyris 

 sphenoldca, which was long known as a fossil before it was dredged in 

 the living state, appear to be absolutely on the point of extinction in 

 the Mediterranean (2), although they are still represented in the broad 

 Atlantic under the designations oi MageUania septigera, M. cranium, and 

 Terehyatula cuhensls. 



Hence it is evident, the French conchologists conclude, that the 

 Mediterranean has lost some of its deep-water species since the 

 Pliocene period. This tendency is still manifested, and it is held to 

 be associated with the gradual rise in the temperature of the Mediter- 

 ranean waters which is about -f 13° C, from below 183 metres down 

 to the bottom. The Mediterranean now resembles an inland sea as 

 compared with the Atlantic, where the temperature decreases as 

 depth increases. The fact of the general uniformity of deep-water 

 temperature, first established by the "Challenger" explorations, 



