﻿Vol. 66.~] SPECIES OF AMMONITES AND BKACHIOPODA. 99 



Note. — Hammatoceras feuguerollense may certainly be placed in 

 the genus Burtonia ; and Ammonites alleoni would be more correctly 

 placed there than in Hammatoceras ; yet the different character of 

 its ribbing may probably lead to separation even from Burtonia, 

 when the species of these genera are better known. 



III. Descriptions of Brachiopoda. 

 Terebratula burtonensis, sp. nov. (PI. XII, figs. 11 & 12.) 



Description. — A much inequivalved, incipiently biplicate Tere- 

 bratulid. Dorsal valve rather flattened, ventral valve very gibbous. 

 Lateral margin with curve projected dorsally in the anterior region ; 

 anterior margin with dorsally elevated, broad, median plication, 

 which is only slightly sulcate — incipient bipli cation. Beak curved 

 over, small, with small foramen hiding deltidial plates. 



Distinction. — Is like T. siderica, S. Buckman/but is a larger and 

 more massive shell, more inequivalve and less biplicate. 



Remarks. — Is apparently one of the T. ventricosa-T. buchnani 

 series, which has attained to imiplication of the raised (dorsal) 

 linguiform pattern, and is beginning to become biplicate. 



Locality, etc. — Prom the Eed Beds of Burton Bradstock (Dorset); 

 about sauzei date or perhaps later. Several more or less complete 

 examples have been obtained. 



Terebkatula lowensis, 2 nom. nov. (PI. XII, figs. 9 & 10.) 



1882. Terebratula buelcmani, var. buckmaniana, S. Buckman (non Walker), Proc. 



Dorset Nat. Hist, & A. F.-C. vol. iv, p. 13. 

 1893. ' Terebratula buckmaniana ' Quart. Journ. Geol. Soc. vol. xlix, p. 489. 



Description. — An obovoid, nearly equigibbous, incipiently bi- 

 plicate Terebratulid. Ventral valve but little more tumid than dorsal, 

 lateral margin almost straight, anterior margin only slightly and 

 broadly M shaped, without dorsal linguiform projection. Beak short, 

 not curving over the dorsal umbo, obliquely truncated by a small 

 foramen. 



Distinction. — T. buckmaniana, Walker 3 (in Davidson) is a 

 longer, narrower, and more cylindrical shell. T. perovalis, Koth- 

 pletz, 4 is comparable, but is certainly not Sowerby's species. 



Be marks. — Though the late Mr. J. P. Walker often spoke of this 

 shell as T. buckmaniana, he generally qualified it as the Dorset 

 form. Other students have done the same, and hence a distinctive 

 name is desirable. The shell is certainly a development of the 



1 Proc. Cotteswold Nat. F.-C. vol. xiii (1901) p. 248 & pi. xiii, fig. 11. 



2 Louse Hill. Louse is due to folk etymology and the west-country habit 

 of adding the sign of the genitive to place-names ; it is not connected with a 

 louse, but is low (Anglo-Saxon hlaw, a hill), the same as in Ludlow, Bledlow. 

 So it seems convenient to adopt the form lowensis for Low Hill. 



3 ' Brit. Jurassic Brach.' (Palseont. Soc.) Suppl. 1S78, pi. xix, figs. 15, 17 only. 



4 ' Geol.-pal. Monogr. Vilser Alpen ' Pakeontographica, vol. xxxiii (1886) 

 p. 100 & pi. ii, figs. 15-16 only. 



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