CEPHALOPODA Ammonites nodulosus 
J. Buckman, 1844. 
Original description 
(1844. — J. Buckman, in Murchison, Geol. of Chelt., New Ed., p. 105, p. 90). 
[405] « A[mimonites] nodulosus, Tab. 12, f. 6. — Keel small ; volutions $ to 6, exposed ; 
ribs many, sharp, nearly straight, terminating near the keel in a slightly raised papilla ; 
aperture ovate ; diameter about 1 1/2 in., thickness 2 lines. 
« LocaLrry. — Lias Shales, Vale of Gloucester. » 
[90] « A[rmmonites] nodulosus (Buckman, Tab. 12, f. 6.) L. S. Vale of Gloucester. 
Cold Pool. » 
OBSERVATIONS 
The holotype cannot be found. There are three specimens which were recognised by my 
father as examples of his species ; they were collected by him from the original locality 
[Cheltenham], and so they are metatypes. Of these three specimens, two shew a longer smooth 
stage, rather stouter whorls, and a rather broader periphery than the example now chosen for 
figuring. This has been selected because it has a distinct keel, while the two others 
possess a very small, barely distinct one ; and the original figure (apertural view) indicates a 
noticeable keel. Further, that figure suggests a thin shell ; but the tenuity depicted in the 
drawing must be incorrect ; evidently so is the dimension given in the description, 2 lines. 
However it may be presumed that thinness was a feature of the original specimen, and 
therefore the thinnest of the three examples has been selected as most conformable to the 
original figure. 
The original description gives fairly full informations, only that it says nothing about the 
smooth stage. That (the miserabilis stage) lasts in the examples depicted up to about 12 mm. 
diameter. Then the ribs gradually appear, and they have small knobs on the outer area ; 
they even begin where the whorl emerges. The description corrects the curious mistake 
made in the drawing (the placing of the knobs on the inner margin) ; the result perhaps of 
drawing the specimen by aid of a mirror. 
Genus. Arnioceras Agassiz (Hyatt. — 1867, Bull. Mus. Comp. Zool., No 5, p. 73) The smooth 
stage in the inner whorls, and the early date at which knobs appear are particular features 
which indicate this generic position. 
Locality and Horizon. — Cold Pool is a farm about midway between Cheltenham and 
Churchdown (Gloucestershire) close to the railway connectine these places. The horizon of 
this species is presumably the same as that of 4. Bodleyi (Pal. U., 36), namely, the 
semricostatus-zone of Sinemurian (Lower Lias). 
Mr. J. W. Tutcher has again placed me under much obligation for the excellent photo- 
graphs which he has made of this species. 
Result. Arnioceras nodulosum (]J. Buckman) Lower Lias. 
1905 S. S. Buchman. 
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PALAEONTOLOGIA UNIVERSALIS. — 71" 
