THE NAUTILUS. 115 



The single species, however, recorded from the Cape Verde Islands, 

 A. milleri Dohrn, (1869, p. 18), so far as can be judged from the imper- 

 fect description, would seem to be a Ferrissia. If so, it probably 

 marks the extreme northern extension of the Equatorial fauna on the 

 west coast. 



The family is not represented at all in the Azores. 



In Algeria, in addition to the species of tlaejluviatilis group, are 

 found the two remarkable species described by Bourguignat and for 

 which he created the genus Brondeh'a, (1862, p. 89), B. drouetiana 

 and gibbosa, which retain the apical whorls in maturity. In this 

 respect they resemble the Tasmanian species of Ancylastrum. 

 Unfortunately the soft anatomy of these forms is, as yet, unknown 

 and, until that is determined, the systematic position of the group 

 must remain uncertain. In all probability, it will be found to be 

 more closely related to Ancylus s. s. than to Ancylastrum. 



In both Brondelia and Ancylastrum the apical whorls are sinistral 

 and the animal is, probably, sinistral also. On the other hand, 

 Ancylus s. s., which loses its sinistrally coiled apical whorls at a very 

 early stage and in maturity has the apex usually more or less turned 

 to the right, never to the left, while the animal is sinistral, is com- 

 monly (Taylor, 1895, p. llo) considered an example of heterostro- 

 phy. As a matter of fact, a careful study of the shells belonging to 

 the different groups of the Ancylidce will show that the species hav- 

 ing the apex turned toward the right are really sinistral in their 

 essential construction. In the same way, Acroloxus with its apex 

 turned to the left and a dextral animal would have also in reality a 

 dextral shell. 



In view of the prevalence of the various forms of the fluviatilis 

 group as a characteristic feature of the fauna of Algeria, it was a 

 cause of great surprise to find among the Ancyli of M. Pallary's col- 

 lection a very distinct and curious species of Ferrissia. 



The genus Ferrissia, for in view of the distinct character of the 

 radula, which will be discussed at length in my final paper on the 

 Ancylidce of South Africa now in preparation, I believe it to be 

 entitled to generic rank, has the most extended range of any group 

 of the Ancylidce. While Ancylus s. s. and Acroloxus are restricted 

 to the Palasarctic Region of the Old World, Burnupia to South 

 Africa, Ancylastrum and Latia to New Zealand, and Lanx and 

 Lavapex to America, Ferrissia, with the exception of the Palae- 



