378 Mr. A. L. Massy on Gephalopods 



margin. Suckers relatively small and placed ratlier far apart, 

 especially in the distal halt' of umbrella region. The space 

 here between two suckers frequently twice the diameter of either 

 sucker. Suckers of extremities of arms perfect, not reduced to 

 papilh^, and extending to within less than half a millimetre 

 from tip of arm. Web much developed, extending nearly one 

 quarter the length of arms. Least development between ventral 

 arms. Web continued on arms in the form of large lateral 

 crests. liadula formed of 7 series of teeth: 1 median, 4 lateral, 

 and 2 marginal. Dental formula 3 2 2 12 2 3. Median row 

 consisting of large acute teeth without lateral denticles. Inner 

 lateral teeth much the smallest, broad at the base, terminating 

 in short conical points. Outer lateral teeth broader and more 

 elongated. Marginal teeth elongated and claw-like. Siphon 

 moderately large. Organ of siphon consisting of a pair of 

 heart-shaped folds, of which the thickened rims are con- 

 tinuous and distinctly projecting all round. Mantle bursiform. 

 Pallial aperture not as large as head. Body soft. Lateral 

 adductor muscles in form of flat bands placed rather close 

 together, the anterior much the smallest, the posterior reaching 

 their greatest width in tlie portion attached to the body. 

 The two cartilaginous pieces in the dorsal mantle are long 

 and rod-like ; they are widest in the anterior portion. The 

 ligula copulatoria * of the hectocotylized arm has from eight 

 to nine lamince copulatoria^ in the concave interior, in the 

 median portion of which there is a flat-topped longitudinal 

 ridge. Calamus brachialis moderately short. Sperm-canal 

 smooth, shallow, and like a white band on surface of arm. 

 General colour vinous, due to an immense number of small 

 light and dark purple and dark red chromatophores distributed 

 on a white ground. Polypus profundicola appears to be very 

 nearly allied to Octopus ergasticus, Fischer, particularly in 

 the form of the hectocotylized arm. The ligula copulatoria 

 is, however, only crossed by 6 or 7 lamince in 0. ergasticus. 

 The hectocotylus is also larger in proportion in P. 'profundicola^ 

 and the arms are longer, and with smaller and more numerous 

 suckers. The web is also more developed, forming large 

 crests on the arms, and the siphon projects much less. The 

 specimens examined consist of 7 males and 7 females, 

 obtained in the trawl at 385-720 fath. The principal dimen- 

 sions of a large male and female are given below. 



* The terms used in describing the different parts of the modified arm 

 are tliose suggested by P. and J. Fischer in "Diagnoses d'especes 

 nouvelles de Mollusques Cephalopodes recueillis dans le cours de 

 I'Expedition scieutifique du Talisman " (1883), Joiu-n. de Conch. 1892, 

 xxxii. p. 297. 



