286 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Family STOMACHETOSELLIDAE Canu and Bassler, 1920 



We created this family for an assemblage of genera based upon 

 American Tertiary species which it was absolutely impossible to 

 classify conveniently in the known families. We believed, indeed, 

 that the family was not limited either to America or to the Eocene, 

 but our zoological studies were then incomplete and we preferred to 

 await further researches. Levinsen, 1909, classed in the family 

 Myriozoumidae a rather anomalous ensemble of forms which did 

 not appear to have any close relationship with Myriozoum. Waters, 



Fig. 118. — Genus Stenopsis Canu and Bassler, 1927 



A, B. Stenopsis fenestratus Smitt, 1873. A. Zooecia, X40 (after Smitt, 1873). 

 B. Operculum, X85. 



C, D. Stenopsis cylindricus, new name. Avicularian mandible and operculum, 

 X85. (After Waters, 1909.) 



1913 (p. 519) has pointed out the artificial character of these refer- 

 ences. 



Among the species classed by Levinsen in Myriozoum and which 

 the preceding authors have changed from family to family, there is 

 an important group having exactly the essential characters of our 

 family Stomachetosellidae, namely Escharoides Smitt, 1867. We 

 have been fortunate enough to discover well preserved recent speci- 

 mens and thus have been able to make studies and comparisons of 

 interest. 



The genus "Escharoides" is an artificial grouping already criticized 

 by Waters in 1909. We have dismembered it, following rigorously 

 the physiological principles which have guided us in our former 

 studies. The new genera thus established are Escharoides Milne 

 Edwards, 1812, Posterula Jullien, 1903, Cigclisula, new genus, 

 Ragionula, new genus, and Dialosula, new genus. 



