116 THE NAUTILUS. 



arctic Region of the Old World (Northern Africa as herein stated 

 excepted) has a world-wide distribution. 



With its apparent metropolis in North America, it has recently 

 been found abundantly in South Africa (Walker, 1912, p. 142), and 

 extends northerly along the east coast of the Equatorial Region and 

 in the Valley of the Nile to Alexandria. 



Ancylus tanganyicensis Smith (1906, p. 184), is a Ferrissia. 



The species collected by Blanford (1870, p. 472), in a small 

 stream near Mai Wahiz, Tigre, an affluent of the Nile (1. c., p. 61), 

 and doubtfully referred by him to the Indian A. verruca Bens., is 

 also a Ferrissia. Blanford's specimens, now in the Indian Museum 

 at Calcutta, was sent in 1908 to the Rev. Prof. Gwatkin of Cam- 

 bridge, England, to enable him to extract and examine the radula, 

 which he informed me was of the Ferrissia type. Through his 

 courtesy the shells were sent to me for examination on their way 

 back to Calcutta. At that time I had no specimens of the Indian 

 species in my collection for comparison and, as I had then no ex- 

 pectation of ever doing any work on the African fauna, I unfor- 

 tunately neglected to make any description or figures. My note, 

 made at the time, was simply that the specimens were Ferrissias. 

 This confirmed Prof. Gwatkin's opinion based on his examination of 

 the radula and settled the generic position of the form, though, un- 

 fortunately, its specific character must remain uncertain until it can 

 be more critically examined. 



There are, so far as I know, no authentic records of the occur- 

 rence of Ferrissia on the west coast of Equatorial Africa. As 

 already stated, it seems probable that the A. milleri Dohrn from the 

 Cape Verdes belongs to this group, but only an examination of the 

 types can definitely determine that question. 



There is every probability, however, that, sooner or later, Fer- 

 rissia will be found to be of general distribution in Equatorial Africa. 



The Indian A. verruca Bens., the Japanese A. baconi Bgt., the 

 Australian A. australis Tate, the New Zealand A. woodsi John., 

 (possibly the non-septate form of a Gundlachia according to Hedley, 

 1895, p. 66), and the Hawaiian A. sharpi Sykes are all Ferrissias. 



This world-wide distribution of Ferrissia is very significant and 

 goes to show that, like certain other fresh-water pulmonate types of 

 similar distribution, it is probably of very ancient origin. And the 

 apparent agreement between its present range and the conditions of 



