CEICK : AKMS OF THE BELEMNITE. 275 



third (c) and fourtli (d) arms are each about 45 mm. long, and each is 

 incomplete distally. Their proximal ends pass into tlie hollow at the 

 base of the arms. The fifth arm {e) cannot be traced for more than 

 about 35 mm., and is obviously very imperfect; its distal end 

 terminates very abruptly, whilst its proximal end passes along the 

 right side of the hollow at the base of the arms ; the booklets are 

 rather large and sparsely situated. The sixth arm (/) is about 

 30 mm. long, and is probably nearly, if not quite, complete, since the 

 distal end is very acute ; proximally it seems to pass under the fiftli 

 arm (e) ; the booklets are very small. The order of the arms cannot 

 be satisfactorily determined. There appear to be three pairs, as in 

 the previous example. The third (c) and fourth (d) seem to lie 

 uppermost, and to constitute one pair. Next to these appear to be the 

 second (b) and fifth (e) arms, of which the proximal ends pass on each 

 side of the hollow at the base of the arms ; these constitute a second 

 pair. The two lowest seem to be the two outer ones, the first 

 (a) and sixth (/), which pass under the second (b) and fifth (e) ; 

 these form a third pair. As to their original length it is not easy to 

 decide, but the opinion of the. present writer is that the third (e) and 

 fourth {d) arms constitute the medium-sized pair; the second {b) and 

 fifth (e) the longest; and the first (a) and sixth (/) the shortest. If, 

 therefore, the aspect of the fossil is dorsal, and the interpretation of 

 the order of the arms is correct, then the medium-sized pair were 

 dorsal ; the longest, lateral ; and the shortest, ventral ; just as in the 

 previously-described example. 



Specimeji No. 3 (PI. XXIII, Fig. 4).— In this example [B.M. 

 No. 39,901] from the Lias of Charmouth, the six arms are preserved 

 within an angle of about 120°, but they are not quite so distinct as 

 in the two specimens already described. The specimen measures 

 128 mm. from the base of the arms to the bottom of the ink-bng. 

 The arms appear to be in the order in which they are preserved ; the 

 two innermost are the uppermost, and the two outermost the lowest. 

 Commencing the description on the left side, the first arm («), which 

 is intercepted distally by the edge of the slab, can be traced for 

 a distance of rather more than 20 mm., when it passes beneath the 

 second arm {b), which it meets at an angle ; the booklets are rather 

 wide apart. The second arm {b), which is also intercepted distally by 

 the edge of the slab, can be traced for about 37 mm. ; and, in the size 

 of the booklets and their distance apart, closely resembles the first 

 arm («). The third arm (c), also imperfect distally, can be traced for 

 a length of about 37 mm. The fourth {d), also imperfect distally, is 

 visible for about 33 mm., its proximal end being apparently connected 

 with the third arm {c). The fifth arm {e), which, judging from its 

 acute distal extremity, appears to be nearly, if not quite, complete 

 distally, can be traced for about 47 mm. ; whilst the sixth arm (/), 

 also nearly, if not quite, complete distally, is visible for a distance of 

 about 37 mm., and then passes beneath the fifth arm {e). The order 

 of the arrangement of the arms is not quite easy to make out, and at 

 one time the present writer was inclined to think that the arms were 

 arranged in pairs thus : ah, cd, ef; in which case probably a lateral 



