64 ANATOMY OF AM ASTRIDE. 



clamastra cyclostoma (Kauai), Amastra magna and aurostoma 

 (Lanai), and Paramastra turrit ella (Oahu), the appendix is 

 moderate in length, about twice as long as the spermatheca 

 and duct. Laminella and Pterodiscus have the same propor- 

 tions. This is probably the more primitive condition, as it 

 agrees also with Leptachatina. 



In a few other species examined, the appendix is extremely 

 long. In Paramastra cylindrica (Waianae Mts.) it is 22 mm. 

 long, five times the length of the spermatheca and duct, the 

 terminal enlargement being nearly half the total length. 



Amastra pullata subnigra is rather different. The appen- 

 dix is 50 mm. long, about 8 times the length of spermatheca 

 and duct, and its terminal enlargement is short. This is the 

 greatest development of the appendix in the Amastridce or 

 Achatinellidfc. The pullata group is highly specialized in 

 both appendix and the sculpture of the embryonic shell. 



It is believed that a comparative study of the appendix will 

 assist materially in the classification of the Amastra. Amas- 

 tra and Leptachatina are the largest and most varied genera 

 of the family. 



The genitalia of the following species are represented on 

 the plates. 



PLATE 15, fig. 1, Laminella gravida. Tantalus Bowl. Male 

 organs, showing the penis extruded. 



Fig. 2, L. gravida. Nuuanu. 



Fig. 3, Laminella tetrao. Lanai. Upper female organs 

 omitted. 



Fig. 4, L. gravida. Tantalus Bowl. Upper female organs 

 omitted. 



Fig. 5, Laminella venusta. 



PLATE 16, fig. 1, Amastra pullata subnigra. App., appen- 

 dix; p., penis; r. p., retractor muscle of the penis; sp., sper- 

 matheca; ut., uterus. 



Fig. 2, Amastra turrit ella. Male organs. 



Fig. 3, Amastra turritclla. Another specimen. 



Fig. 4, Pterodiscus rex. Terminal ducts. 



Fig. 5, Amastra badia. 



