chick: on acanthotetjthis feeussach. 59 



li & /, the smallest. Eesides these six radial elevations, the counter- 

 part (Fig. 2) shows that the membrane also projected somewhat 

 about midway between the two backwardly -directed (on the slab) 

 radial elevations, although this projection was not furnished with 

 any sharp elevation like the rest. Thus the membrane seems to 

 have been attached to the arms by seven ligaments. In some recent 

 forms this membrane has also seven lines of attachment ; it is 

 not united with either of the tentacular arms, and the small con- 

 nection between the two dorsal arms is fi'equently single at its base, 

 although subsequently divided. The greatest diameter of the buccal 

 disc, including its radial elevations, is 24 mm., the diameter of the 

 central opening being about 12 mm. The two ligaments marked 

 i & j respectively include between them the bases of the two arms 

 d &, e\ the small ligament marked I appears to have been situated 

 at the base of the arm marked /; the ligaments m k, n seem to 

 have been connected with the bases of the arms h 8o g respectively ; 

 whilst the arms a & h were probably attached to the extension of 

 the membrane marked o. But, as we have already stated, the exact 

 order of the arms cannot be definitely ascertained. A slight 

 crumpling of the membrane is perceptible between the radial 

 elevations. The line of symmetry appears to pass through o and 

 midway between ^ & j. "VVe have been able to recognize only eight 

 arms, but we do not know that any recent Octopod possesses a buccal 

 membrane such as has just been described, although in some species 

 the bases of the arms are united by a membrane. In the recent 

 ten-armed Cephalopoda, however, the presence of a similar membrane 

 is by no means infrequent. Further, in some members of the 

 Onychoteuthidee (to which the present genus seems to be allied) 

 not only is there such a membrane, but the ligament attaching 

 the buccal membrane to the two dorsal arms is frequently, if not 

 always, single at its proximal but bifid at its distal extremity. If 

 the same condition of things existed in the genus AcantJioteuthis 

 as in these recent Cephalopoda, the ligament marked o would be 

 dorsal and pass to the two dorsal or first pair of arms, then i & J 

 would be attached to the ventral or fourth pair, ^ & ^ to the ventro- 

 lateral or third pair, and m & n to the dorso-lateral or second pair. 



Immediately below the buccal membrane, and enclosed by an 

 obscure, obtuse, slightly elevated ridge, there is a pear-shaped area 

 about 33 mm. long and of about the same width ; it is some- 

 what constricted at the base of the arms, being here only about 

 28 mm. wide, and attains its greatest width at about its mid-length ; 

 posteriorly it contracts suddenly, and the lateral ridges uniting 

 together, combine with an obscure median ridge, which extends from 

 the ligament marked o, into a feeble elevation about 1 1 mm. wide ; 

 this is continued backwards for a distance of about 12 mm., and 

 terminates in an obtuse point. At its greatest width the margins of 

 this area are slightly interrupted, and between this median line and 

 the outer boundary on the left side there is an obscure oval area about 

 17 mm. by 13 mm., the longer axis being antero -posterior. The 

 pyriform area is probably the remains of the head, the position of 



