278 PROCEEDINGS OF THE MALACOLOGICAL SOCIETT. 



and very thin portions of nacreous material. Possibly, therefore, the 

 aspect of the animal that is presented is dorsal ; in that case, and 

 provided the interpretation of the relative position of the arras is 

 correct, the medium-sized pair of arms is dorsal; the smallest pair, 

 ventral ; and the longest, lateral. 



Specimen No. 6 (PL XXIII, Fig. 3). — This example [B.M. 

 No. 82,895], preserved on the surface of a slab from the Lower Lias 

 of Lyme Regis, Dorset, displays the arms arranged fan-shaped, with 

 some brownish material (possibly the remains of the jaws) at their 

 coalesced proximal ends, and the ink-bag bearing upon its surface 

 very delicate fragments of nacreous matter. From the base of the 

 arms to the posterior end of the ink-bag the specimen measures about 

 153 mm., the greatest width of the ink-bag being 30 mm. In this 

 example the number of the arms is not quite so clear as in the other 

 specimens. Five arms are plainly shown, but the disposition of a few 

 remaining booklets is rather difficult. Each arm is slightly curved. 

 Commencing on the left, the first fairly complete arm {a) measures, 

 including the small booklets at its proximal end, 53 mm. It seems to 

 be complete distally. On the left-hand side of this arm, at about its 

 mid-length, there are some detached booklets, which probably belonged 

 to this arm. The second arm {h), apparently complete distally, 

 measures from its distal end to the coalesced bases of the arras 54 mm. 

 Lying by the side of this and almost parallel to it is the third arm (c) 

 of about the same length. The fourth arm {d) is not quite complete 

 distally, and appears to lie on the third. The fifth arm {e) can be 

 traced for a distance of about 52 mm, from the coalesced bases of the 

 arms, and its distal end appears to be nearly, though not quite, 

 complete. At about its mid-length and on its right side, there are 

 three or four booklets (/), which from their regularity seem to have 

 belonged to another arm, but, if so, its proximal portion is confused 

 with that of the fifth arm {e). In this example the order of the arms 

 is not at all clear. If the outermost arm on each side constitutes 

 a pair, one would expect to find an even number of arms in the space 

 between them. Three can be made out with certainty, but it is not 

 easy to decide which formed the pair and which is the odd one. It 

 seems, however, highly probable that the second {h) and fourth {d) 

 arms {b and d) constituted the pair, and that the third arm (c) is the 

 odd one. Again, the little booklets on the right of the fifth arm {e) 

 are somewhat difficult to interpret. If they formed part of another 

 arm it is not easy to see with which other arm it formed a pair. On 

 the whole, therefore, this specimen is not quite easy to intei-pret, and, 

 further, the relative position of the arms is very obscure. One or two 

 of the booklets of the second arm {h) rest upon those of the first (a), 

 whilst some of the booklets of the third (c) rest upon those of the 

 second {b), but the greater part of the third ann {c) underlies the 

 fourth (d), and one or two booklets near the base of the latter rest 

 upon those of the fifth arm {e). 



The conclusions arrived at in the present paper may be summarised 

 as follows: — (1) That in the Lower Liassic seas there existed 

 a Cephalopod having six uncinated arms ; (2) that this Cephalopod 



