50 STROBILOPS, S. G. ENTEROPLAX. 



five folds are seen in immature shells (PI. 12, fig. 9, Lake 

 Helen, Florida). 



In a young shell from Miami 1.2 mm. diameter (PI. 8, fig. 5) 

 there are no basal folds, but the two parietal lamellae are well 

 developed. Folds are present but small in a shell 1.5 mm. 

 diameter, and at 2.2 mm. (PI. 8, fig. 6) they are longer than 

 in an adult of the same lot (PI. 8, fig. 7) . 



Mexican specimens from Tampico (PL 7, fig. 5) and from 

 Valles, San Luis Potosi (PI. 7, fig. 4) are like those of Jamaica; 

 the few seen have three basal folds. 



The form I described as S. huhhardi stevensoni (PI. 8, figs. 

 1-7) is identical with vendryesiana. It was distinguished from 

 huhhardi by the smooth base, somewhat wider umbilicus and 

 three basal folds — the type of huhhardi having more basal 

 sculpture and four folds. Large series which I have examined 

 and opened appear to show that the characters relied upon are 

 inconstant, and moreover, are those of vendryesiana. 



Subgenus Enteroplax Gude. 



Enteroplax Gude (as a section of Plectopylis) , Science 

 Gossip VI, October, 1899, p. 149. Type by original designa- 

 tion P. quadrasi. 



The shell is thin, low conoidal to almost discoidal in form; 

 the edge of the parietal caUus thickened and raised, prominent 

 where the parietal lamella joins it; infraparietal lamella 

 emerging, both lamellfe with smooth or serrate (not nodose) 

 edges, and penetrating a half whorl; usually there is a low 

 radial callus across the parietal wall at their inner ends. 

 There is no columellar lamella. A radial series of few or many 

 basal folds is immersed from a fourth to a third of a whorl 

 back from the peristome. Soft anatomy unknown. 



Distribution : Philippine Islands. 



This little group is well characterized by the raised parietal 

 callus, somewhat like that of the typical Polygyras, and tlie 

 absence of a columellar lamella, as in S. huhhardi of the Sec- 

 tion Discostrobilops. The parietal lamellae are either smooth 

 at the edge, as in some Tertiary species of Strohilops, or the 



