PAPUINA. 139 



boivini (MoDatsber. Berl. Akad. Wissensch. 1877, p. 277, pi. 2, f. 11 

 -13). The writer has examined the soft parts of P.frwgilla, vexil- 

 laris, moseleyi and conscendens. 



Papuina is an exclusively arboreal genus, being strongly con- 

 trasted in this habit to its allies Thersites and Chloritis. The shell 

 is of lighter structure and brighter color than in these terrestrial 

 groups, somewhat approaching that of Cochlostyla a case of con- 

 vergence of external characters from similar habits. The teeth dif- 

 fer from those of allied groups, Thersites, Chloritis, Planispira, in 

 the great breadth and bluntness of the cusps, a structure correlated 

 with arboreal habits. The jaw is more delicate than in the allied 

 genera. 



The great variation observed in the genitalia and teeth of the 

 species examined, shows that here lies a wide field for future cultiva- 

 tion. These features are no doubt characteristic of minor groups in 

 the genus, and their investigation will lead to valuable results in the 

 classification of the group, and secondarily may be of use in the 

 study of its geographical distribution and migrations. The arbo- 

 real habit has evidently been long established, for otherwise we 

 should not have so profound a remodeling of the dentition. 



The geographic limits of the genus are on the northwest Halma- 

 heira, on the southeast, the New Hebrides group. There are two 

 principal centers of specific radiation: New Guinea and the Solo- 

 mon archipelago. The former of these has peopled the Moluccas, 

 Queensland and the Louisiades. The species of Java, Sumatra and 

 India referred by authors to this genus belong to other groups? 

 mainly Satsuma. 



Subdivisions. 



Section Papuina. Shell having the outer lip well expanded,, 

 baso-columellar lip reflexed. 



Section Dendrotrochus. Shell trochoid, the columellar lip not in 

 the least expanded or reflexed. 



Section Papuina (restricted). 

 (Group of P. boivini; Solomon and New Britain groups.) 



P. congrua Pfr., vii, 4. P. hargreavesi Ang. vii, 9. 



P. chancei Cox, vii, 5. hargravesi auct. 



amphizona Pils., vii, 5. P. gamelia Ang., vii, 10. 



