Reviews: Huxley—Belemnitide. 69 
peculiar cuticle of the ‘guard’ (in B. elongatus), are extremely 
well shown in Liassic specimens (from the collections above men- 
tioned) beautifully figured in the plates of this Monograph. ‘The 
Author states, that, with an ink-bag 1:4 inch long and °55 inch 
broad, the shell of B. elongatus would be (from apex to mouth of 
‘ phragmacone’) 5:35 inches long, the ‘guard’ being 2} inches long 
from its apex to its expansion at the base of the ‘phragmacone,’ 
and -25 inch broad; and he suggests that ‘these measurements may 
enable one to form a rough estimate of the size of ‘guard’ which 
appertained to any detached ink-bag, and vice versa. We may also 
suggest, that, finding an ink-bag in the clay, the collector may 
hence be led to make careful examination throughout a calculated 
distance, in a line with it, for other parts of the animal. According 
to the figured specimen of the above measurements, the arms and 
hooks would be about two inches in advance of the ink-bag. 
Naturalists, having now a perfect Belemnite before them, can 
affirm, with Buckland and Woodward, the existence of the ink-bag 
as a matter of direct observation. The ink-bearing ‘ Belemnosepia’ 
of Agassiz and Buckland is therefore a Belemnites, and does not 
belong to the Teuwthide or Squids. Mr. Huxley dwells also on the 
relationship of Belemnites and Belemnoteuthis, the latter of which, 
he thinks, will prove to have a ‘ pro-ostracum’ of peculiar form. 
Acanthoteuthis, founded on incomplete remains in the Solenhofen 
Oolite, may belong either to the better known Belemnites, Belemno- 
teuthis, or Plesioteuthis, or even to Keleno. 
The new Cephalopodous Genus described in Professor Huxley’s 
Monograph has been hitherto imperfectly known by a fragmentary 
specimen in the Geological Society’s Museum, and figured and 
described by De la Beche in 1829 as Orthocera elongata (Geol. 
Transact., 2nd ser., vol. ii. p. 28, pl. 4, fig. 4); but its real nature 
was first revealed by some fine specimens found by Mr. Day in the 
lower part (Belemnite-beds) of the Middle Lias near Lyme-Regis. 
It consists of a narrow, cylindrical, structureless ‘guard,’ about 
3 inches long, about 1th inch thick, and containing a long tapering 
‘ phragmocone,’ the chambers of which much resemble those of an 
Orthoceras. The ‘conotheca’ passes upwards into a remarkable 
‘pro-ostracum,’ nearly 12 inches long ; at its base it is a flat band 
only -35 inch broad, narrowing to about’2 inch; in its upper half, 
widening and becoming convex, it is ‘5 inch broad, and then tapers 
to a point. Jt has a polished surface, wrinkled transversely just 
below its widest part. It is composed of concentric lamelle, with 
fibres perpendicular to their planes, as in the ‘ guard’ of an ordinary 
Belemnite. No ink-bag, hooks, nor beaks have yet been found 
associated with this internal shell, which is generically distinguished 
from other Belemnitide by the form and structure of its ‘ pro- 
ostracum,’ its long, narrow, deep-chambered ‘ phragmocone,’ and its 
cylindrical ‘ guard.’ 
‘The genera hitherto enumerated,’ says Mr. Huxley, ‘in the family of the 
Belemmte, characterized among the Dibranchiate Cephalopoda by possessing 
