Classification of the Brachiopoda. — Schuchert. 157 
JMartiniopsis, Waagen 18^ 
Ambocoelia, Hall 1860. 
Reticularia, McCoy 1844. 
Spiriferus, Blainville 1827. 
Spirifera, J. de C. yowerby 
1835. 
Brachythyris, McCoy 1844. 
Fusella, Mct'oy 1844. 
Hysterolithiis,Quenstedt 1871. 
Family Nucleospirid.*:,* Davidson 1882. 
Retziina' and Dayina?, Waagen 1883; Anazygidio (part), Davidson 
1884. 
Dayia, Davidson 1882. 
Hindella, Davidson 1882. 
Nucleospira, Hall 1858. 
Retzia, King 1850. 
Trigeria, Bayle 1878. 
Rhynchospira, Hall 1859. 
Trematospira, Hall 1857. 
Eumetria, Hall 1864. 
? Acumbona, White 1862. 
? Uncinella, Waagen 1883. 
Family ATHYRii)/E,t Phillips 1841. 
]. Subfamily Atiiyrin.t:, Waagen 1883. 
Meristina, Hall 1867. 
Athyris, Davidson 1853 (not 
McCoy 1844). 
AVhitfieldia, Davidson 1882. 
Bifida, Davidson 1882. 
Athyris, McCoy 1844. 
Actinoconclius, McCoy 1844. 
Spirigera, d'Orbigny 1847. 
Euthyris, (^uenstedt 1871. 
Anomactinella, Bittner 1890. 
Cleiothyris, King 1850 (not 
Phillips 1841). 
Seminula, McCoy 1841. 
Spirigerella, Waagen 1883. 
Dioristella, Bittner 1890. 
Amphitomella, Bittner 1890. 
Plicigera, Bittner 1890. 
Tetractinella, Bittner 1890. 
Pentactinella, Bittner 1890. 
Kaj'seria, Davidson 1882. 
Diplospirella, Bittner 1890. 
Euractinella, Bittner 1890. 
Pexidella, Bittner 1890. 
Anisactinella, Bittner 1890. 
1.' Subfamily Meristellin^, Waagen 1883. 
Meristella, Hall 1860. 
Pentagonia, Cozzens 1846. 
CToniocoelia, Hall 1861. 
Charionella, Billings 18*11. 
Merista, Suess 1851, 
t-amarium, Hall 1859. 
? Clorinda, Barrande 1879. 
*In the NucLEospiBiD^ and Athyrid^e the brachia are directed laterally. The primary 
lamelhe are Htniight but for a short distance from tlicir point of attachment, then bending 
backward, recurve to form the spiral cones. In the SriitiFKiuD.-E they remain direct. 
The apex of the V-shaped loop in the Nucleospiiuu.e terminates in a more or less long 
simple process, which may be hooked at its outer end. 
tThe apex of the V-sliaped loop has two processes which, in the Athtrin.«, are first 
short and then become elongated to such an extent tliat they enter between the first and 
second revolution of the primary lamelhe of each cone, and in some genera continue to 
the apex of the brachia. In the MERisTBi.LiN.e, the two processes of the loop bend upon 
themselves, return, and join at their point of origin, thus resembling the handles of a 
pair of scissors. 
