82 
NAUTILOIDEA. 
B. tyrannus is B. Bohemiciis, the whorls of which, however, increase 
more rapidly in breadth, and it has a smaller umbilicus ; its body- 
chamber is also shorter, and wider at the aperture. 
Professor Blake regards the two species tyrannus and Bohernicus 
as identical, but on comparison they appear to me to be sufficiently 
distinct from each other at all stages of growth to warrant their 
being kept separate. 
Horizon. Lower Ludlow. 
Locality. Ledbury. 
Eepresented by a fine specimen, presented by G. H. Piper, Esq., 
F.G.S., and another example, very imperfect, probably from Dudley. 
Barrandeoceras Holtianum, Blake, sp. 
1865. Lituites Holtianus, Salter, Cat. of Museum of Practical Geology, 
p. 75 (name only). 
1882. Nautilus Holtiafius, Blake, British Foss. Ceph. pt. i. p. 211, 
pi. xxviii. f. 1. 
Sp. Char. “ The rate of increase and breadth of the last whorl 
vary very little in the dififerent examples ; the greatest breadth is 
•54. The section may be more or less due to compression, as all 
examples are more or less imbedded in the stone. The shape is 
always as in the type in adult forms, but more quadrate in the 
young, the maximum thickness observed being 4 the breadth. On 
the outer whorl of some are seen slight undulations of growth 
towards the inner side, and a few backward-curving lines ; on the 
inner whorls there are about 40 gently backward-curving feeble 
ribs. The surface is also covered by very fine riblets, 11 per line, 
and by transverse epidermids in some specimens. The body- 
chamber has a slight tendency to leave the coiled portion, and 
reaches on the average about of a whorl [in length]. The inner 
side of the aperture is slightly produced, and the middle has a 
forward curve, and in some there is a slight constriction there. 
The septa are from 20 to 34 per whorl; fewer at first, but in- 
creasing in number continually ; not very convex in the suture, 
but curving forward very rapidly both inside and outside, making 
almost a funnel-shaped lobe at the former place. The siphuncle is 
not accurately determined in any, but one example had some indi- 
cations of an internal siphuncle, but in another it looks more 
probably central. 
“ The great proportionate breadth of the outer whorl distinguishes 
this from N. Bohernicus. It is quite symmetrical, and is therefore 
