3 <M 



M. SASAKI : 



Length of right second arm measured up from mouth 



Greatest thickness of arms 



Diameter of largest sucker 



85 mm. 



[O 



2-3 M 



As regards the affinity of the genus, Hoyle has assumed that it stands 

 closest to CirrotaitJiis, as agreeing with that genus in having the suckers 

 arranged in single series and the arms united by a broad umbrella. It 

 seems to me exceedingly doubtful if this view can be held up when the 

 following facts are taken into consideration : Firstly, AinpJutrctus is 

 entirely devoid of the dorsal cartilage, fins and brachial cirri, all which 

 CirrotaitJiis is in possession of. Secondly, Amphitrctus has a pair of 

 oviducts, while in Cirrotcntiiis and its allies that duct is always unpaired, 

 — a difference which, in my view, goes far in indicating a rather remote 

 relationship between the two genera. (Ijima and Ikeda's statement that in 

 A. pvlagicus the oviduct occurs in a pair, I have confirmed by personally 

 examining the original specimen described by them. I have found that the 

 oviducts are in character essentially of the same type as those of Polyptis. 

 The oviduct proper and the vaginal part are both of a moderate length, 

 connected together by a roundish oviducal ball. The vaginal part is thicker 

 than the oviduct proper, and terminates at a point far posterior to the anus). 



Rather it seems to me that Ainphitrctus is more nearly related to the 

 Polypidae than to Cirrotcutliis. This is indicated especially by the general 

 agreement in the arrangement of internal genital organs. 



It was pointed out by Ijima and Ikeda that Avipliiirctas approaches 

 Alloponis in several respects. This is indeed true to a degree, but the 

 structure of the hectocotylus seems to point to the former being nearer to 

 the Polypidae than the latter. 



II. Diagnoses of Four New Species of Polypus. 



Polypus orulutn sp. nov. 



? Octopus areolatus, Hoyle 1886, diali. Rep. p. 86, pl. pi. iii, figs. 6, 7. 

 ? Octopus occllatus, Appllöf 1886, Jap. Cephal. p. 8. pi. i, figs. 1-3. 



Adult small, nearly 150 mm. in total length and 40 mm. in mantle- 



