T. Davidson — Upper Silunan Brachiopoda. 151 



Silurian Monograph, Prof. J. Hall has, at p. 166 of the Twenty- 

 Eighth Annual Eeport of the New York State Museum of Natural 

 History (1879), proposed a new genus, Bhynchotretce, for the 

 reception of Dalman's species, and which he characterizes in the 

 following words : — 



" Shell triangular, surface with angular plications, ventral beak 

 straight, produced beyond the dorsal beak, extremity perforate, the 

 foramen with an elevated margin ; space between the foi'amen and 

 the hinge-line occupied by a deltidium in two pieces, being divided 

 by a longitudinal suture, and transversely striated. Valves articulated 

 by two slender curving teeth, proceeding from a broad curving 

 hinge-plate in the ventral valve, which fit into corresponding sockets 

 in the dorsal valve. Crurge rising from near the dorsal beak and 

 curving into the ventral cavity, and thence recurved towards the 

 dorsal side, and probably uniting, as shown in fig. 4 (Fig. 11 of our 

 Plate). Structure fibrous and apparently very minutely punctate." 



It seems quite evident that Prof. Hall has not actually seen the 

 short Terebratula-shaped loop represented in his restored fig. No. 4 

 (Fig. 11 of our Plate), for he says in his description, "and probably 

 uniting, as shoion in Jig. 4 " — and in the explanations of his fig. 4 he 

 adds, " the additional features of the loop represented in this figure 

 have not as yet been satisfactorily determined." In order, if 

 possible, to ascertain the internal character of this species, I asked 

 the Rev. Norman Glass to develope the interior of several well- 

 preserved specimens of Bh. cuneata from the Wenlock Limestone of 

 Benthall Edge, and all of them showed only the two small curved 

 lamellas not attaining a third of the length of the dorsal valve, as 

 in Rhynchonella proper. In no instance did Mr. Glass discover any 

 indication of a loop. I would therefore leave Dalman's species with 

 Bhynchonella until, on positive evidence, it can be shown to be 

 generically separable. 



9. Bhynchonella Dayi, sp. PI. V. Fig. 9. 



Obtusely deltoid or sub-pentagonal, wider than long, valves 

 moderately convex, and divided into three almost equal lobes. 

 Ventral valve not quite as deep as the dorsal one, divided by a broad 

 well-defined mesial sinus, beak small, showing a small circular 

 foramen margined by a deltidium, surface of valves ornamented with 

 some fourteen or sixteen angular ribs, of which four form a well- 

 defined mesial fold, the ribs being slightly bent upwards at the 

 front, lateral margins of fold wide and flat. Length 5^, width 6, 

 depth 3^ lines. 



Obs. — This small species is well distinguished from young 

 specimens of the same age of Rh. borealis, with which it had been 

 confounded by its less triangular shape, as well as by the ribs of its 

 fold being bent upwards close to their frontal extremity. In size 

 and in number of ribs Bh. Dayi somewhat resembles small 

 examples of the Jurassic L'h. tetraeclra. 



This small species was found by Mr. George Maw in the Wenlock 

 Limestone of Benthall Edge, as well as in the Wenlock Shales 



