THE NAUTILUS. 123 



Pilsbry did not take into consideration the disposition of some cos- 

 mopolitan genera in certain points. Thus Pupa is represented but 

 by one species in New Zealand, and Succinea not at all ; and not- 

 withstanding there are perhaps no two genera of Nephropneusta 

 more cosmopolitan than Pupa and Succinea. The genera Physa, 

 Planorhis, Limncea, Ancylus (with Latia), Cyclas, Pisidium, Neritina, 

 Helicina, Melania are cosmopolitan but have disappeared with time 

 in some localities. Some genera now confined to one locality were 

 once cosmopolitan like Partula, now Polynesian only, but found in 

 the European eocene by Oppenheim and in the Florida miocene by 

 Heilprin. Other genera may have been more restricted in distribu- 

 tion as I presume with the Chilinas of Archiplata, which shall be 

 discovered I assume some day in mesozoic beds of Australia or New 

 Zealand. It is to be studied which are the genera or families of 

 Nephropneusta which once spread cosmopolitan over the globe. 

 I can name Patula, Succinea, Pupa and j^evhaps some Zon it idee, Bul- 

 imulus with Partula, Bulimus with allied genera. 



If we compare the molluscan fauna of South America and New 

 Zealand, it is evident that it is impossible to expect to see the rela- 

 tions as very close. Both have undergone enormous modification 

 since they were disconnected in the beginning of the tertiary period 

 according to the theories of Mr. Hutton and myself The archiplatan 

 province of South America has in the later tertiary received 

 immigrants from North and Central America (such as Campylcea) and 

 from the Archamazonian province (as Streptaxis, Ampullaria, Glaba- 

 ris, etc.). New Zealand on the other hand, received immigrants from 

 the adajacent islands and from Australia, and this Australian 

 element is perhaps in part Asiastic. The genera common to Archi- 

 plata and New Zealand thus may be very few. Anyone who studies 

 land shells from Archiplata, excluding the northern immigrants will 

 be astonished by the extreme poverty of the fauna. And what remain 

 as presumably autochthonous, are such genera as Pupa, Succinea, 

 Patula, Bulimulus, Bulimus. 



I am quite aware that these facts are not sufficient to prove the 

 ancient connection of Archiplata and New Zealand ; but it should 

 also be stated that no facts contradictory to such connection have 

 been adduced. The argument can be conclusive only when we know 

 better the paleontological history of the fauna. What is known 

 to-day is in favor of my theory, as I have demonstrated in relation 

 to the fresh-water shells. Also the fossil marine shells will probably 



