ANIMALS. 89 
Propuctus Horripus, J. Sow. Brown, Fossil Conchology, pl. lvi, figs. 13, 14, 1843 (?). 
— eo a8 De Verneuil, Bull. Soc. Géol. de France, 2™° série, t. i, 
p- 29, 1844. 
— = m Desor, Min. Conch. de Sowerby, p. 352, pl. cexi, eccxix, 
figs. 1, 2, 1845. 
— caLvus, J. de C. Sow. Desor, op. cit., p. 577, pl. ecclx, ecclxv, figs. 3-5, 1845. 
—_ HoRRIDUS, J. Sow. Geol. Russia, vol. i, p. 222, 1845. 
STROPHOMENA AcuLuATA, Sch/. Schmidt, Petrefacten-Buch, p. 25, pl. iv, fig. 6 a, 6, 1846. 
Propuctus HorriDvws, J. Sow. Geinitz, Grundriss, p. 521, pl. 21, fig. 17 a, 6; pl. xxii, 
fig. 8, 1846. 
— = we Tennant, Strat. List Brit. Fossils, p. 88, 1847. 
_ _— » De Koninck, Mém. Soc. Roy. Liége, t. iv, pp. 266-72, 
pl. xv, fig. 1 a, 6, ¢, d, 1847. 
— a 5 King, Catalogue, p. 8, 1848. 
= _— i Howse, T. N. F. C., vol. i, p. 256, 1848. 
= si Geinitz, Versteinerungen, p. 15, pl. vi, figs. 1-14, 1848. 
Diagnosis —“ Quadrangular, with a large furrow along the middle, eared, thorny. 
Ears prominent, sub-cylindrical. Beak incurved, large.’ (J. Sowerby.) 
The researches of Dr. de Koninck (whose synonymy for the last century I have 
fully availed myself of) into the bibliographical history of this species, have shown 
that it is the most anciently-recorded Productus known, having been first noticed by 
Hoppe so early as 1745. 
Productus horridus is found under so many forms, that any one might, at first, be 
tempted to divide it into a number of specific groups; but I am fully convinced that a 
more intimate acquaintance with all the various appearances and conditions under 
which the species occurs, cannot but lead to the conclusion that it is not so far 
divisible. In Plates X and XI will be found some of the principal varieties, which, it 
requires to be remarked, are characteristic of certain localities: thus the Whitley 
specimens (Pl. XI, fig. 1) are narrower and comparatively higher than those found at 
Humbleton (PI. XI, fig. 4) and Derbyshire, and they possess a shallower median 
furrow; while the Garmundsway (PI. X, figs. 29, 30, 31) and Thickley specimens are 
intermediate in these respects; besides, the Humbleton and Derbyshire varieties have 
not the square form possessed by the latter. The former are also more decidedly 
ridged in the longitudinal sense (compare fig. 23, Pl. X, with fig. 3, Pl. XD. Similar 
varieties occur in Germany. I procured at Kamsdorf a specimen equally as wide 
as any found at Humbleton; whereas all the Gliicksbrunn specimens I have seen are 
narrow, like those occurring at Garmundsway. ‘There also appears to prevail a differ- 
ence in the form of the boss or cardinal muscular fulcrum, which is trilobed, with the 
lobes convex, in the Garmundsway examples (Pl. XI, fig. 12); but bilobed, with the 
1 Mineral Conchology, vol. iv, p. 17, 1823. It affords me much pleasure to state that Mr. J. de C. Sowerby 
has kindly lent me for illustration (vide Pl. XI, figs. 2, 3) two beautiful specimens of this shell, one of 
which served as the original or type of the species. (Vide Min. Conch., vol. iv, p. 17, pl. ecexix, fig. 1.) 
m 
