THE BRITISH FOSSIL BRACHIOPODA. 379 



2. Meekella, C. A. White and St. John, ' Transactions of the Academy of Sciences of 

 Chicago,' p. 120, 1868, type Meekella (Plicatella), striato-costafa, Cox. Dr. White 

 states that the " broad dental lamellae with the three rostral chambers, the plicated shell, 

 and the unusually robust form, clearly separate the genus from Hemipronites. The 

 rudimentary or obsolete area of the dorsal valve, and non-perforated and usually distorted 

 ventral beak, separate it from Klitambonites, 1 Pander=Orthisina, d'Orb. 



3. Streptorhynchus, King, 1850, type St. pelaryonatus, Schlotheim. " A Stropho- 

 menidia, insequivalved, striated or ribbed, with the hinge approximating or equal to the 

 width of the valves ; umbones more or less divaricating, the large one irregularly twisted ; 

 fissure covered with a deltidium ; dental plates small, projecting more at the base of the area 

 than at its apex." Its small dental plates, &c, distinguish it from Meekella. King tells us, 

 at p. 107 of his "Permian Fossils," that the genus consists of a small number of known 

 species, and that Strept. senilis, Phill., Strept. pelargonatus, Schl., and Strept. spurius, 

 Braun, are the only forms with which he was acquainted. Since then several forms have 

 been placed in the genus Streptorhynchus, such as Strept. crenistria, and Strept. 

 arachnoidea, which King had incorrectly placed in Ort/iis. One of the most beautiful 

 species of the genus is the Strept. pectiniformis, Dav., described and figured in the 

 'Quarterly Journal of the Geological Society,' vol. xviii, pi. i, fig. 17, 1861, and 

 according to Waagen, subsequently confounded by Messrs. White and St. John with a 

 fossil much resembling it externally, which had been discovered in America by Cox, and 

 to which he had given the name of Plicatella striatocostata, the type of White and St. 

 John's genus Meekella. I am informed by Dr. Waagen that subsequently, after 

 examining Punjab specimens of Strept. pectiniformis, Meek arrived at the conclusion that 

 they were devoid of septa in the ventral valve, and consequently were not referable to 

 Meekella ('Final Report on Nebrasca,' p. 176). 



4. Orthotetes, Fischer, 1829, ' Bull, des Naturalistes de Moscou,' p. 375, and ' Orycto- 

 graphie du Gouvernement de Moscou,' p. 131, tab. 20, fig. 4, 1837. The Russian type 

 agrees with the Strept. crenistria of Phillips. Dr. Waagen writes that, although the descrip- 

 tion of this genus in the Russian work is unsatisfactory, yet if the laws of priority are to be 

 followed, Fischer's name will have to be retained for shells agreeing with his figure and 

 Strept. crenistria. If so, it will be necessary to remove several British species classed with 

 Streptorhynchus, and to place them with Orthotetes. This subject will, however, require 

 further consideration and investigation. 



5. Berbyia, Waagen, 1884, type D. grandis, Waagen. I am uncertain with 

 respect to the characters of this genus, which Dr. Waagen informs me by letter he has 

 proposed for species with a median septum in the ventral valve and two diverging 

 septa in the dorsal one. Strept. senilis serves as an example. Dr. Waagen describes 

 several species of Derbyia, which I should have thought referable to Orthotetes. 



6. Strophomena, Rafinesque, 1820, has caused much confusion. It should, I think, 

 be restricted to forms that agree with Strophomena rhomboidalis. 



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