Geographical Distribution of the Terebratulae. 189 



Summanj. 



1. Of tlie thirty-nine species cited in the foregoing analysis, 

 thirty-five belong to the Old World, only four to the New. 

 None of the species are common to both, with the single excep- 

 tion of Terehratulina caput-serpentis of the North European and 

 Lusitanian provinces, which ranges in a modified form (7^. sep- 

 tentrionalis, Couthouy) to the eastern shores of North America. 

 Two species of Terebratula have been described by Dr. Gould 

 in Wilkes's 'Exploring Expedition' {T. caurina and pulvinata), 

 from Puget Sound, Oregon ; but I have not seen them. 



2. The distribution of subgenera illustrates a few characteristic 

 centres of creation. Megerlia, Morrisia, Argiope, and Thecidea, 

 all have their homes in the Lusitanian province, — one species 

 only, Argiope cistellula, passing into the Celtic province, which 

 has no centre of specific creation of its own. Kraussia has its 

 home in the South African province, embracing four species. 

 A fifth species, K. Lamarckiana, is found in the Australo- 

 Zealandic province; but the apophysis, on which the subgenus 

 is founded, is abnormal in its structure. 



3. Of subgeneric types widely removed, Bouchardia presents 

 curious instances. B. tulipa, a solitary species on the shores 

 of Brazil, is undoubtedly identical in type with B. fibula and 

 Cumingii, which are natives of Australia and New Zealand, 

 though no faunas of any two provinces can be more generally 

 dissimilar. The same may be said of Waldheimia and Terebra- 

 tella; but these subgenera are more abundant in species and in- 

 dividuals, distributed in local centres of creation of more vary- 

 ing specific character. 



4. Of specific types widely removed, a notable instance is 

 presented in Waldheimia globosa of California, and W. lenticu' 

 laris, a native of New Zealand. Not only are these very remote 

 species of the same specific type, but the difference of their 

 specific details is scarcely appreciable. 



5. The most characteristic assemblages of species are those 

 of Terebratulina in the North European and North Asiatic pro- 

 vinces, of Waldheimia in the Panamic, of Terebratella in the 

 Magellanic, and of Morrisia and Argiope in the Lusitanian 

 province. 



6. Species are fewest within the Tropics. The Indo-Pacific 

 province, which extends from Austraha to Japan, and from the 

 Red Sea and east coast of Africa to Easter Island in the Pa- 

 cific, embracing three-fifths of the circumference of the globe 

 and forty-five degrees of latitude, yields only three species — 

 Waldheimia picta, Terebratulina Cumingii, and Terebratella san- 

 guinea ; and of the first two, very few individuals are known. 



7. Species, with few exceptions, are very local. The excep- 



