106 
The American Geologist. 
February, 18W 
but sometimes bifurcated. Shells plicate : structure distinctly 
punctate. 
Parazyga, H. and C. 1893. 
Acambona, White 1862. 
Hustedia, H. and ('. 1893. 
Retzia, King 1850. 
Trigeria, Bayle 1878. 
Homoeospira, Hall and Clarke 
1893. 
Rhynchospira, Hall 1859. 
Ptychospira, H. and ( '. 1893- 
Eumetria, Hall 1864. 
Treniatospira. Hall 1857. 
B. Subfamily Hindellix.e, n. subfaiu. 
Loop with a single process which may be simple, or may 
articulate in a ventral septal socket, sometimes (rarely) being 
sharply recurved terminally. Shells smooth, finely spinose, or 
plicate ; structure impunctate. 
A n o p 1 o t h e c a, Sandberger 
1856. 
Bifida, Davidson 1882. 
Ccelospira, Hall 1863. 
Leptocuelia, Hall 1857 and 1859 
Vitulina, Hall 1860. 
? Anabaia, Clarke 1893. 
j Hindella, Davidson 1882. 
| Whitfieldella, H. and < !. 
1893. 
Meristina, Davidson 1882 (not 
Hall 1867). 
Nucleospira, Hall 1858. 
Hyattella. H. and C. 1893. 
B 1 . Subfamily Athyrin^e, Waagen 1883. 
The single process of the loop with distal bifurcations which 
may Or may not terminate between the first and second volu- 
tions of the spirals. Shells smooth, lamellose spinose, or with 
a few sharp, non-alternating plications ; structure impunctate. 
Meristina, Hall 1867. I Cleiothyris, King 1850 (not 
Athyns, Davidson 1853 (cot Phillips, 1841). 
McCoy 1814). 
Whitfieldia, Davidson 1882. 
Glassina, Hall and Clarke 
1 S93. 
Athyris, McCoy 1844. 
Spirigera, d'Orbigny 1817. 
Euthyris, Quenstedt 1871. 
Actinoconclnis. McCoy 1844. 
Seminula, McCoy 1841. 
Spirigerella, Waagen 1SS3. 
Anomactinella. Bittner 1890. 
Pomatospirella. Bittner 1S'.)2. 
Amphitomella, Bittner 1890. 
Plicigera. Bittner 1890. 
Tetractinella, Bittner L890. 
Pentactinella, Bittner L890. 
B 2 . Subfamily DiplospirinjE, n. subfam. 
Bifurcations of the loop process very long, lying between 
tlie volutions of the spirals, and continuing with these to their 
outer ends. Sometimes there is an additional process on the 
