part 4] JURASSIC chrois^ologt : lias. 319 



Table XX. — Comparison of Figures. 

 Species. Cotteswold Club paper. Monograph. 



PI. fig. PI. fig. 



A. planorhis i, 1, 1 a, 1 5. 



A. buclclandi i, 2,2 a. i, 1-3. 



A. hirchii i-, 3. xxxii, 5,6. 



Do. do i, 3 a. xxxii, 7. 



Do. do i, 3h. xxxii, 8. 



A. ang.ulatus i, 4,5. 



A. sauzeanus ii, 1 a, b, c. viii, 1-3. 



Do. do. ii, 1 cZ. viii, 5. 



A. semicostatus ii, 2,3. 



A. turneri ii, 4. xii, 1,2. 



Do. do ii, 4 a. xii, 5. 



Do. do ii, 4 b. xii, 6. 



A.hroo]:ii ii, 5 side. vi, 4.. 



Do. do ii, 5 front. 



Do. do. ii, 5 a. vi, 5. 



A. rotiformis iii, 1. v, 4. 



Do. do. iii, 1 a. 



A. conyheari iii, 2,3. ii, 1,2. 



Do. do. iii, 3 a. ii, 3. 



A. ohtusus iv, 1 a, 1 &, xxi, 1,2. 



Do. do iv, 1 c. xxi, 5? 



A. multicostatus iv, 2 a, 2 b, 2 c. 



(A. hisulcatus in text). 



A. hucklaiidi. — Same figures in Mon. as C. C. paper, just under 

 half of the natural size. Thickness of whorl given by Wright in 

 text in both cases =33 per cent., but figure shows only 25'5. 



A. hircliii. — Mon. figs, appear to be tracings of C. C. figs. : 

 there is the same omission in both — failure to show inner row of 

 tubercles in front view. The suture-line is said to be from a 

 Bredon specimen. The point was whether Hgs. o ki ^ represented 

 a specimen from this locality, and if it was of the natural size 

 what it could be. I come to the conclusion that it is from Lyme 

 Kegis and is a large shell reduced, on these grounds : — 



In the C. C. paper, p. 179, Wright says, 'The finest specimens 

 of this shell are found near Charmouth and Lyme Regis.' On 

 p. 178 he gives the 'transverse diameter of a large specimen 

 8 inches,' and the proportions he gives work out as 203, 19, 

 21*5, — ; he also mentions that the shell has 7 turns and 32 to 34 

 lateral costfe. The C. C. example has 7 turns, has 33 spines on 

 outer row of last whorl, and the ])roportions of the figure are 84, 

 22, 18 (22), 61. I think that the figure represents the 8-inch 

 example reduced — the dimensions of aperture transposed by 

 Wright — and that Avhen he transferred the figures to the Mon. 

 he called it, in error, a small shell. It will be interesting to see 

 where this leads. 



In the Mon. Wright describes (p. 332) his large specimen as 

 1(30 mm. diam., and the proportions that he gives work out as 

 160, 22, 22, 60. The figure, however, is 166, 22, 23, 58. He goes 



