418 G. C. Crick — On Goniatitcs, Nautilus, etc. 



The siphuncle is near the periphery, its centre being only 

 2-75 mm. from the surface, where the whorl is 13 mm. high. 

 Judging from another specimen, 1 the siphuncle was more nearly 

 central in the young shell, e.g. where the height of the whorl was 

 only 2*5 mm. 



The species may then be characterized as follows : — 



Shell discoidal, evolute, rather rapidly increasing, with a large 

 central vacuity ; greatest thickness at about one-third of the height 

 distant from the inner edge of the whorl, about three-eighths of the 

 diameter of the shell ; height of outer whorl rather more than three- 

 eighths of the diameter of the shell. Whorls at least two; inclusion 

 almost nil; umbilicus shallow, wide, nearly three-eighths of the 

 diameter of the shell, its sides sloping and convex. Whorl truncated- 

 oval in section, a little higher than wide, scarcely impressed by the 

 preceding whorl; periphery flattened, the central portion slightly 

 raised above the rest and feebly concave, broad, about two-thirds 

 of the corresponding height of the whorl in width ; sides — outer 

 two-thirds flattened, very feebly convex, convergent, 2 the rest 

 strongly convex and continuous with the convex, relatively broad, 

 inner margin. Length of body-chamber not seen. Chambers leather 

 shallow, measured at the middle of the lateral area about three- 

 tenths of the corresponding height of the whorl apart; suture-line 

 with a V-shaped peripheral lobe, nearly as wide as the peripheiy, 

 a somewhat broader external saddle situated on the periphero-lateral 

 angle, and a single, wide, shallow, lateral sinus, but neai'ly straight 

 on the inner portion of the whorl, and with a well-marked annular (or 

 internal) lobe. Siphuncle near the periphery, rather small. Test — 

 the lateral area ornamented with fine transverse stria3, crossed by 

 delicately crenulated longitudinal lines, both becoming finer in the 

 adult, the latter losing their crenulations and gradually disappearing 

 first from the inner portion of the sides, and afterwards from near the 

 periphery, leaving in the adult merely fine transverse delicate stria? ; 

 the central portion of the periphery with exceedingly delicate back- 

 wardly-curved striae, crossed by very obscure longitudinal lines, 

 much coarser longitudinal lines (about six) occupying a narrow 

 band near each boundary, and diminishing in strength from the 

 angular margin inwards. 



Unfortunately the locality of the specimen in the Gilbertson 

 collection, which Phillips figured as Nautilus tetragonus, is not quite 

 certain. It is labelled " Northumberland ? " 



One of Phillips' types of G. evolutus. now in the York Museum, 

 came from Flashy, four miles north-west of Skipton, Yorkshire. 

 The species has also been recorded from Chrome Hill, Derbyshire; 3 

 and from the Poolvash Limestone in the Isle of Man." 1 



Mr. G. H. Morgan, F.G.S., of Liverpool, recorded 5 the species in 



1 From Graig fawr, Prestatyn, Flintshire, and kindly sent to me for examination 

 by Mr. G. H. Morton, F.G.S., Liverpool. 



2 i.e. converging towards the plane of svmmetry external to the periphery. 



3 G. Sharman and E. T. Newton, " Geol. N. Derbvshire," 2nd ed., 18S7, 

 Appendix 1, p. 182: Mem. Geol. Surv. 



4 J. H. dimming, " Isle of Man," 1848, p. 357. 



5 Proc. Liverpool Nat. Field Club for 1894 (1895), p. 23. 



