16 STROBILOPS. 



Oligocene and Miocene beds, are very numerous. All of the 

 early authors referred the species to Helix. E. S. Morse, 1864, 

 was the first to demonstrate the intricate internal structure of 

 the shell, and to recognize that it belongs to a special genus, 

 whicli he named Strohila — a name which unfortunately proved 

 to be a homonym. Sterki (Nautilus, VI, 1892, pp. 3, 6) re- 

 moved the genus from the Helicidse to the family Pupidse 

 (Pupillidae). Hanua (1922) described and figured the anat- 

 omy, and proposed the name Strobilopsidae. Several articles 

 by the present writer (1893-1909) enlarged our knowledge of 

 American forms, pointed out the occurrence of the genus in 

 eastern Asia, and indicated the relationship of the Philippine 

 forms of the subgenus Enteroplax to Strohilops. Finally, W. 

 Wenz has reviewed the species in two excellent articles: 

 "Die fossilen Arten der Gattung Strobilops Pilsbry und ihre 

 Beziehungen zu den lebenden," 1915, and "Zur Kenntnis der 

 Gattung Strobilops Pils.," 1916. 



Of the twenty-eight Recent forms now known — nineteen 

 species and nine subspecies — I have not seen specimens of the 

 following four : Strohilops veracruzcnsis crossei, 8. salvini, 8. 

 diodontina and 8. trochospira. The type specimens of 13 

 species and 6 subspecies have been examined; the remaining 

 three species are known to me by specimens from the original 

 collectors. 



Classification. 



The first attempt to classify the species of Strohilops into 

 natural groups was made by W. Wenz (1915, pp. 84-86). 

 Considering the fossil species only, he proposed three groups. 



1. Group of 8. diptyx, for the species diptyx, fischeri, hoett- 

 geri, suhconoidea, duvali. This line begins in mid-Oligocene 

 time and runs to mid-Pliocene, in central and western Europe. 

 Perhaps 8. elasmodonta belongs here: it differs from all the 

 others by possessing an interparietal lamella. 



2. Group of 8. costata, with the species costata, joossi, 

 tiarula, romani, lahyrinthicula. Probably 8. monilia and 8. 

 ynenardi, and evidently 8. headonensis and 8. pseudolahy- 

 rinthica are to be added. This series ran from Eocene prob- 



