450 ME. S. S. BUCKMA.N ON THE BAJOCTAN [Aug. 1895, 



like ' cynocephala ' ; but when critically compared with the French 

 figures, they are seen to have the mesial fold just a little shorter and 

 less pointed ; also 3-4 instead of 4-5-plait lateral folds, the exca- 

 vation between these folds less pronounced, while the shell is slightly 

 smaller altogether. 1 



This species occurs where its bed is exposed, along a line of 

 country from Chiselborough (near Ham Hill) in Somerset to 

 Chideock (near Bridport) in Dorset, or to Burton Bradstock — a line 

 which runs nearly due north and south. The most notable localities 

 are Stoke Knap, Whatley, and Middle Cbinnock (near Haselbury). 

 In the Bradford-Abbas district its horizon is not found, no strata 

 being present ; they should come between the ' Dew Bed ' and the 

 ' Paving Bed,' which, though in contact, are non-sequential. 



As a typical example of this species has not been figured in the 

 brachiopod literature of this country, an illustration of such a 

 specimen from Stoke Knap is given in PL XIV. fig. 1. 



The species exhibits 1- and 3-plait varieties ; but these are very 

 decidedly rare. Exact proportionate numbers of the forms would not 

 be obtained by counting a series in a cabinet, because the 1- and 

 3-plait forms have been specially sought out. 



Ehynchonella cynopeosopa , 2 sp. n. 



1851. BhyncJionetta cynocephala, Davidson (non Richard), ' Monogr. Brit. Fossil 

 Brachiopoda,' vol. i. pt. iii. p. 77, Pal. Soc. pi. xiv. figs. 10-12. 



1857. Rhynchonella cynocephala, Lycett, ' Cotteswold Hills,' pi. i. fig. 7 a, b. 

 1882. Mhynchonella cynocephala, Witchell, ' Geology of Stroud,' pi. i. fig. 13. 



A Rhynchonella — one of the pugnaces. The mesial fold narrow, 

 very considerably elevated, generally biplicate, with its side-margins 

 nearly parallel. 



This species is excellently figured by Davidson, and it has passed 

 under the name of cynocephala. If, however, his figures be com- 

 pared with those given in the ' Bulletin ' of the Geological Society 

 of Prance, 3 particular differences may be noted. In the first place, 

 the mesial fold is very much more elevated, and it is so turned over 

 the beak that a line from the tip of the mesial fold to the beak will 

 be nearly at right angles with a line from the beak to the edge of 

 the lateral fold of the perforate valve — a character well shown in 

 Davidson's fig. 11 b, which should be compared with the French 

 fig. 5 a held in the same position. Then, in the second place, the 

 mesial fold is of a more uniform breadth, so that its side-margins, in 

 an anterior view of the perforate valve, are more nearly parallel — 

 features particularly brought out in the drawings by Davidson, 

 Lycett, and Witchell. Thus the two points of the end of the mesial 

 fold are not only farther apart, but separated by a wider notch. 



1 Since the above was written, a species even more like the French form has 

 been found by myself at Withington in the Cotteswolds, in the sandy ferru- 

 ginous beds (scissi hemera), so that I have much hesitation in saying that 

 btephensi is a synonym cf cynocephala. 



a Kvvo7rp6aui7ros, dog-faced. 3 See preceding article, p. 449. 



