CRICK : ARMS OF THE BELEMNITE, 271 



specimen, the present writer has been enabled to see a photograph of 

 the fossil.^ Now the booklets in Acanthoteuthis were pointed at their 

 proximal ends just as in the genus jBelewnoteuthis ; in fact, it is not 

 quite certain that the two genera are distinct." The photograph, 

 however, though not pai'ticularly sharp, shows that the proximal ends 

 of the booklets were thickened, and not sharp ; in fact, they much 

 more closely resemble those figured by Professor Huxley as belonging 

 to Belemnites than the booklets of Acanthoteuthis. But Dr. Jaekel 

 describes the fossil so completely — the outline of the body with 

 a terminal triangular fin near the hinder end on each side, the head, 

 the funnel, the arms, and the remains of a dorsal pen — that if the 

 remains had belonged to a Belemnite one would have expected to have 

 been preserved, if not the guard, at least some indications of the 

 phragraocone, but the author does not allude to these. Tlie various 

 structures here referred to are not at all clearly indicated in the 

 photograph, though it must be admitted that, as already stated, this 

 is by no means so sharp as one could have wished. So far as can be 

 judged from the photograph, the present writer sees no reason for 

 regarding the fossil as generically distinct fi'om the forms referred to 

 in the present paper. 



Assuming, then, tliat the seventeen examples of Liassic uncinated- 

 armed Cephalopoda in the British Museum above alluded to belonged 

 to Belemnites, the number of arms may be considered. In several 

 instances the arms are so well preserved that there can be no doubt 

 whatever about the arrangement of the booklets. These were arranged 

 in a double row of opposite hooks along each arm, the hooks being 

 largest at the mid-length of each arm, and gradually diminishing in 

 size towards each end. The hooks were placed on the inner surface 

 of the arm, and, in the contracted state of the arm, the bases of each 

 pair of booklets were almost in contact. The arrangement is shown 

 very clearly in one of the arms {d) of an example [B.M. JN'o. 47,020] 

 in the British Museum collection that is described below as specimen 

 No. 5 (PL XXIII, Fig. 5). Since in these Liassic examples the fleshy 

 part of the arms is not usually preserved, in determining the number 

 of the arms exhibited in any particular specimen it must be remembered 

 that each arm is represented hj a double row of booklets. 



Of the seventeen examples of Liassic Cephalopoda in the British 

 Museum collection exhibiting uncinated arms, the only specimens 

 showing the arms in association with a guard are the two examples 

 already referred to that were figured and described by Professor 

 Huxley ^ as Belemnites Briiguierianus (PI. I, Figs. 1, \a) and 

 B. elongatus (PI. I, Figs. 2, 2a) respectively. Unfortunately the 



' The photograph included two specimens. Dr. Augermann, during a \\s\i to the 



British Museum, identified for the present writer the example described by 



Dr. Jaekel. 

 ^ See E. Angermann, " Ueber das Genus Acanthoteuthis, Miinst., aus den litho- 



graphischen Schiefern in Bayeni" : Neues Jahrb., Beil. Bd. xv, Heft 1 (1902), 



pp. 205-230, pi. vi. 

 » Op. cit. 



