BRACHIOPODA. 175 



their structure is indicated, among other things, by their possessing, through- 

 out the existence of the individual, a condition of the loop which was but an 

 immature phase in Atrypa. 



The mode of attachment of the crura to the primary lamellae has not 

 before been fully described, though the figures given by Whitfield and 

 QuENSTEDT approach the truth most nearly. Among tlie illustrations of the 

 genus is one (Plate LIV, fig. 17) showing a malformation or hypertrophy of 

 one of the crura, which had become detached from the hinge-plate durin"- 

 the life of the animal. The effort to renew the connection was not success- 

 ful, but resulted in an extravasation of testaceous matter about the broken 

 extremity; such, in fact, as has taken place about the disconnected extremities 

 of the loop. 



Subgenus GRUENEWALDTIA, Tschernyschew. 1885. 



PLATE Lll. 



This name has been proposed* for the species Terebratula latilinguis, Schnur,f 

 originally described from the middle Devonian at Gerolstein. This species was 



Fig. 154. no. 165. 



^inraU oY GruenewaldtialatiHnguU,^c\u\m\ In lig. 155, the pedicle valve is the lower ami llie two mediuii dots 

 represent sections of llie primary lamella;. (Tscheenyschew.) 



considered by Kayser as a variety of Atri/pa reticular is. '^ The Russian speci- 

 mens have the pedicle-valve very convex, the relative convexity of the valve 

 in A. reticularis being reversed in this species. From the description and 

 figures given by Tschernyschew, the spiral cones have their bases lying against 



* Die Fauna iles Untei en Devon am West-alihan^e lies Urals, jip. 46, 89, pi. vi, figs. 75-77. 

 t Ziisanimenstellung' and Beschreibung ssammtlicher im Ueberg'ung.egebirge iler Eifel vorkoramenden 

 Bi'achiopoden, p. 183, pi. xxv, fig 1, 1853. 



I Zeitschr. der deutsch. geol. Gesellsch., vol. xxiii, p. 545. 1871. 



