F. E. Cow]jer Reed — New Fossils from Haver tor chcest. 363 



Remarhs. — There are only two specimens of this shell in 

 Mr. Turnbull's collection, and one (No. II) is somewhat laterally 

 compressed and the other rather crushed. But sufficient characters 

 are preserved to show we have to deal with a new species. The 

 character by which the genus Archinacella ^ is principally dis- 

 tinguished from Tryblidium'^ is the possession of a continuous 

 muscular loop instead of separate pairs of muscles arranged round 

 the shell. The definition of the genus Arcliinacella is given by 

 TJlrich, its founder, as follows (op. cit., p. 821) : — " Shell 

 patelliform, ovate to subcircular, usually widest anteriorly, forming 

 a low cone with the apex in front of the centre and often sub- 

 marginal. Muscular scars forming a continuous band. Surface 

 markings concentric only. Type, A. powersi, Ulrich." 



A species which seems deserving of comparison with our Kedhill 

 form is A. valida (Sardeson) ^ from the Trenton Group of 

 Minnesota ; and Billings' Metoptoma simplex * from the Calciferous 

 formation appears to have precisely the same contour and shape. 



Abchinaoella aff. rotunda, Ulrich. (PI. XX, Figs. 10, 10a.) 

 There is a smaller and apparently distinct species of Archinacella 

 occurring in the Eedhill and Slade Beds, which is, however, scarcely 

 sufficiently known at present to warrant a new specific name. It i& 

 nearly circular in shape, strongly convex, with the sharp pointed 

 apex vertically above and slightly overhanging the anterior margin ; 

 the shell is highest in the middle, and the apex is rather depressed 

 and incurved, being only about half the maximum height of the 

 shell above the margin. No surface-markings are distinguishable. 

 This species appears to resemble Ulrich's A. rotunda ^ from the Utica 

 Group of Iowa. 

 Dimensions : 



Length 5-5 mm. 



Width 6-5 mm. 



Height 3-Omm. 



Horizons.— (1) Kedhill Beds; (11) Slade Beds. 



Localities. — (I) Eedhill Quarry; (II) Quarry at Upper Slade. 



Bellerophon (SiNUiTEs) cRYPTioDS, sp. nov. (PI. XX, Figs. 12-14.) 



Shell involute, closely coiled, subglobose, sides somewhat flattened, 

 greatest thickness at umbilicus, back narrowly rounded ; outer 

 ■whorl completely embracing and hiding inner whorls, and increasing 

 rather rapidly in size to mouth ; umbilicus minute (exposed in 

 casts) ; section of whorls semi-elliptical to parabolic ; aperture 

 higher than wide, not expanded laterally ; outer lip thin ; inner lip 

 more or less reflexed and thickened ; dorsal sinus moderately deep, 

 broadly V-shaped ; apertural lobes rounded gently to sinus, where 

 margin is rather suddenly and sharply curved inwards. Surface of 



1 Ulrich: op. cit., p. 828. 



2 Lindstrom & Angelin : Fragmenta Silurica (1880), p. 15. 



3 Ulrich : op. cit., p. 832, pi. Ixi, figs. 14, lo. 



* Billings: Palsoz. Foss. Canada, vol. i (1865), p. 346, fig. 334. 

 ° Ulrich : op. cit., p. 835, pi. Ixi, figs. 24, 25. 



