992 PBOF. d'ahcv w. Thompson on [Dec. 18, 



abdominal vertebra?. The posterior of these in the forms pre- 

 viously described have hseinapophyses, which are absent in Apsetta 

 thompsoni. 



Whilst the resemblances are sufficiently obvious therefore to 

 demand the inclusion of this form within the Solei-pleuronectince, 

 the differences entitle it to be considered a distinct genus. 



4. On a rare Cuttlefish, Ancistroteuthis robusta (Dall) 

 Steenstrup. By D'Arcy W. Thompson, C.B. 



[Received December 18, 1000.] 



A large Cuttlefish had been thrown up on the beach at Unalaska 

 shortly before my arrival there in the summer of 1896. It had 

 been preserved in salt, and was very kindly given me by Mr. J. 

 Stanley Brown, of the North American Commercial Company. 

 The specimen is now iu the Museum of University College, 

 Dundee. It is plainly identical with Onychoteuihh robusta (Dall, 

 MS.) Verrill, and, though not complete and not in a state to admit 

 of dissection, it furnishes some additions to our knowledge, and 

 settles the generic position, of that interesting species. 



The following are the measurements of our specimen : length 

 from tail to the free border of the mantle, 62 inches ; total length 

 from tail to beak, approximately 70 inches ; from the tail to the 

 end of the arms, approximately 8 feet. The breadth across the 

 broadest part of the tins is 27 inches, across the mantle-orifice 

 12^ inches. Length of fin -attachment 34 inches. 



The general shape of the body is almost eveuly conical, very 

 slightly attenuated between the fins, which latter extend over just 

 about one half the length of the mantle. The head is rather small 

 and narrow, the eyes not prominent. The broadest part of the 

 fins is about 27 inches from the apex, which they reach, and 

 towards which their trapezoidal outline is sharply narrowed. 



The funnel measures, from anterior to posterior edge in the 

 middle line, Ik inches long, and about 11 h inches from its apex to 

 its basal angle. Its free portion is about 3 inches long, below 

 which point a double muscular fold or " bridle " unites it to the 

 neck. The funnel possesses a large internal valve. The anterior 

 orifice is about 3 inches from the base of the arms ; its dorsal margin 

 overlaps the orifice in the form of a hood about If inches in antero- 

 posterior diameter. The lateral grooved surfaces at the base of 

 the funnel are each about 5| inches long, \h inches broad at the base, 

 and about 1 inch broad close to the anterior rounded extremity : 

 they are soft and flattened, and the cartilages within are imper- 

 ceptible ; they have a free edge all round, about a quarter of an 

 inch wide but somewhat broader anteriorly. The corresponding 

 surface in the mantle forms a light-coloured streak with dark 

 edges, with no conspicuous thickening. On the back of the neck 

 is a third similar surface about 8 inches long, and If inches broad 



