HELICID^. 29 



Hyalosagda^ Albers, 1860. Shell scavcel}^ perforated, depressed 

 hj^aline, thin ; whorls 5-7, the last excavated at the base ; aper- 

 ture obliquely lunar; peristome acute, columellar margin scarcely 

 dilated, slightly reflexed. H. aimilis^ Adams. Jamaica. 



PATULA, Held, 1837. (Eyryomphala, Beck, 1837. Delompha- 

 lus, Agassiz, 1837. Euryomphala, Herm., 1846. Discus [part], 

 Ads., 1855.) Shell perspective!}^ umbilicated, discoidal or tur- 

 binated, depressed, rugose or striated ; whorls gradually enlarg- 

 ing ; aperture rounded, unarmed by teeth; lip simple, sharp. 

 Jaw smooth or slightly striated, with a more or less marked 

 median projection. 327 sp. Universal." 



Pyramidido,, Fitz., 1833. H. rupestiHs, Drap. Europe. 



Patulastra^ Pfeiffer, 1878. TJncharacterized. H. ampla, Pfr. 

 Mexico. 



Z)^scus, Fitz., 1833. H. perspectiva^^&y. United States. H. 

 rotundata^ Miill. (xciii, 6). Europe. 



Planogyra, Morse, 1864. Shell minute, perfectly flat above, 

 umbilicus moderate ; whorls very convex, the last one sharply 

 ribbed. H. asteriscus, Morse (xciii, 7). United States. 



Goni/odiscus, Fitz., 1833. H. solaria^ Menke. Europe. 



Acanthinula, Beck. 1846. (Zoogenites, Morse, 1864.) Shell 

 perforated, giobosely turbinated, with a brownish plicately 

 ribbed or aculeate epidermis ; whorls 4-5 ; aperture rounded ; 

 peristome tliin, somewhat expanded, its extremities approaching. 

 H. harpa^ Say (xciii, 99). H. aculeata, Miill. (xciv, 40). 8 sp. 

 United States, West Indies, Europe. Buccal plate transversely 

 and longitudinally striate, its edge slightly indented with a 

 middle projection. Viviparous, containing embryos in various 

 stages of development at the same time. 



Trichodlscus, Strebel and Pfeffer. Shell subdepressed, widely 

 umbilicated, banded, beset with fine bristle-bearing warts ; peris- 

 tome shortly reflected. H. coactiliata, Fer. Mexico. 



Thysanopho7^a, Strebel and Pfeffer. Shell flat or conical, 

 widely umbilicated, brown, with longitudinal plaits and rows of 

 epidermal fringes ; aperture simple. H. impura, Pfr. Mexico. 



Lyra, Shuttlew. Shell with revolving lines. Canaries. 



Patulopi<is, Strebel and Pfeff"er. Shell nearly flat, keeled, 

 ribbed, with wide umbilicus. H. carinata, S. and P. Mexico. 



Pseudohyalina, Morse, 1864. (Chanomphalus, Strebel and 

 Pfeffer.) Distinguished from Patula by the minute size and 

 more moderate umbilicus. P. minuscula, Say, etc. United 

 States, Mexico, etc. 



Anguispira, Morse, 1864. Shell large, depressed tui'binate, 

 banded or striped ; umbilicus moderate. P. alternata, Say 

 (xciii, 8). United States. 



Stephanoda, Albers, 1860. Shell widely umbilicated, thin, 

 depressed, plane above, convex below, with 5-7 close volutions, 



