CLASSIFICATION OF THE BRACHIOPODA. 117 



ramified adductor scars ; the reniform impressions, after dividing the above-named 

 muscle, extend by an outward obhque curve to near the margin, when turning 

 abruptly backwards and inwards, terminate at some distance from their origin. Under 

 the adductor, more towards the centre of the valve, exist two elevations (perhaps, 

 brachial eminences), 



Obs. In 1847, Colonel Helmersen proposed the genus Aulosteges^ for a remarkable 

 shell abundantly found in the Permian Limestones of Mount Grebeni, in Russia, and 

 described by JVl. de Verneuil, under the name of Orthis Wan^enheifnip' and which the 

 Russian author considered distinct from both Prochctus and Strophalosia of King. In 

 outward aspect it differs from Productus by its remarkable area and pseudo-deltidium, 

 recalling certain shapes of Orthisina, but internally, the muscular scars, cardinal process, 

 and reniform impressions are essentially like those of Productus, varying but little in 

 their position and details. According to Professor King's present views, Aulosteges is a 

 link connecting Productus and Strophalosia, but it seems to me, that if this shell is to be 

 separated from either of those genera, it can only claim a sub-generic rank; its animal 

 must have been very similar to that of Productus. 



Geo. range. — Hitherto only one species has been discovered, which beloligs to the 

 Permian age,^ 



Genus — Productus, Sowerbg, 1814. 



Type — P. Martini, Sow., or semireticulatus, Martin, sp."* Int., PI. IX, figs. 217 — 223. 



Gryphites, sp., Hoppe, Walch., Schlotheim, &c. 



Anomia, Ba Costa, Chemnitz. 



Pyxis, sp., Chemnitz. 



AnomitE echinat^ et Concha filos^, TJre. 



Anomites, Martin, Schloth. (part). 



Arca, sp., Bruguiere. 



Trigonia, sp., Parkinson. 



Productus, Sowerby, Fleming, Deshayes, Be Verneuil, V. Buch, De Koninck, If Orbigny, 



King, and of the generality of Authors. = 

 Tridacna, sp., Lamarck. 

 Terebratula (part), De Blainville, Rang. 

 Proton ia, Link. 



Arbusculites, Murray, Teste, Bronn. 

 LepTjENA, Dalman (part), Fischer de Waldheim, Goldfuss, J. de C. Sowerby, Phillips, &c. 



' Bull. Phys. Math, de St. Petersburgh, vol. vi, No. 9. 



2 Geol. of Russia and Ural Mountains, vol. ii, pi. xi, fig. 5, 1845. 



' Professor King informs me that his Productus umbonillafus may require to be placed in the sub- 

 genus Aulosteges. 



* According to M. de Koninck, Productus Martini, Sow., would be a synonyme of Anomites semi- 

 reticulatus of Martin. 



^ Pander places in Productus shells we consider to belong to the genus Leptcena and Orthis. 



