INVERTEBRATE PALiEONTOLOO Y. 283 



little sinuous below; external thickening of the outer lip well-developed, the 

 lip being crenate or smooth within ; inner lip thickened, and provided with 

 from one to three well-developed plications, or folds ; surface marked with 

 spiral, sometimes punctate striae. 



The foregoing diagnosis is drawn up so as to include three subgeneric 

 groups, presenting the following distinguishing features: 



1. cinulia, Gray (typical). 



Shell with outer lip smooth within ; inner lip bearing a single, 

 very oblique, moderately prominent fold, continued downward into the 

 outer lip at the base of the aperture; spire typically abruptly attenu- 

 ated. — (Type as already cited.) 



2. oligoptych, Meek. 



Shell with spire much depressed and obtuse; outer lip smooth 

 within, and very slightly sinuous at the base of the aperture; inner 

 lip bearing a single, very prominent, nearly transverse plication, or 

 tooth, at the base of the columella. — (Actceon concinnus, Hall and Meek.) 



3. avellana, d'Orbigny. 



Shell with the thickened outer lip crenate within, and the inner 

 bearing from two to three or four prominent, nearly transverse plica- 

 tions, or teeth. — {Avellana incrassata, d'Orbigny.)* 

 The group Avellana was made, by d'Orbigny, to include the type-species 

 of Cinulia, Gray, along with other species belonging to a somewhat different 

 section, such as A. incrassata, A. Hugardiana, &c, d'Orbigny. As the latter 

 group, however, does not seem to me to differ more than subgenerically from 

 Cinulia proper, I have, elsewhere as well as here, retained it in that sense, 

 under d'Orbigny's name Avellana ; and now also propose another small sec- 

 tion for the reception of such forms as Actceon concinnus, Hall and Meek. 

 As thus defined, the genus Cinulia is related to Ringicula, Deshayes, but 

 differs in having a more globose form, a more depressed spire, and particu- 

 larly in wanting the deep sinus at the base of the columella, seen in that 

 genus. So far as known, it is peculiar to the Cretaceous rocks. 



"lna revision of the family Aetaouidw, published in 1863, in the Am. Jour. Sci. and Arts (2d. ser.), 

 XXXV. 1':',. I also included, as another subgenus under Cinulia, a group for which the name Eupiycha was 

 proposed, with Auricula decurtata, Sowerby, as its type. I now regard that group as forming a distinct 

 genus, and having since observed that the name proposed for it was pre-occupied for a genus of Ltpidop- 

 tera (described by Hiibner in 1816), now propose to name it Eriptycha. In addition to the type-species 

 E. decurtata, it will include the three East Indian Cretaceous species, E. globata and E. larvata, Stoliczka, 

 described by Dr. Stoliczka under the generic name Evptycha ; and E. oviformis described by Professor 

 Forbes as Nerita oviformis. 



