BRACniOPODA. 15 



Torfl)ratula.l!i', Leach, MSS. iSlS, Atin. c\ Mar/. N. H. \x.27:i. 

 Tcicbrutulidiu, Grny, Syii. B. M. lS40 ; 1S42, 85, 92 ; Sow. Ann. 

 N. II. 2n(l SIT. ii. AM\, 1S4S ; Wicgm. Arch. 1849, 98. 



M'Coi/, C(irl). Foss. Irclant!. 



Khuj, Ann. ly May. Nat. Ilisl. xviii. 26. 



Forhe.'i t^ Hanley, Brit. Moll. ii. 343. 



irOrh. Cours Paleont. 80. 1849. 

 Tercbratiilucen, Menke, iSyn. oil. 2. 95, 1830. 

 Terc'hratuliicea, piirt., Anton, Verz. Conch. 12. 21. 

 Tercbratulaccjc, Menke, Syn. ed. I. 5(), 1828. 

 Les TerAratuk's, Fe'niss. Tab. Syst. 1821. 



Rant/, Man. Moll. 258. 

 Tercbratuliujc, Ayass. Nomen. 1847. 

 Linguhc, part., Eichw. Zool. Spec. i. 2/5. 

 Thecididir, part. (Megathyris), D'Orb. Ter. Cr4t. iv. 

 Cyclothyridte, Phillips, Pal. Foss. Cornwall. 



Synopsis of Tribes and Genera. 



A. Loop attached to the hinge-plate. — Terebratulanina. 



1. Terebratula. 



2. Terebratulina. 



3. Waldheimia. 



B. Loop attached to the septum in the middle of the dorsal 

 valve. — Magasina. 



4. Terebratella. 



5. Trigonosemus. 



6. Magas. 



/. Bouchardia. 



8. Megerlia. 



9. Morrisia. 



10. Kraussia. 



C. Loop attached to the surface of valve. — Argiopina. 



11. Argiope. 



Tribe 1. TEREBRATULANINA. 



Shell usually oval, valves convex, margins even or only slightly 

 waved ; binge-line curved ; beak of the larger valve perforated, 

 the foramen quite at the apex ; deltidium of two pieces, often 

 blended ; internal skeleton consisting of a slender shelly loop, 

 not attached in the middle to the valve. 



