400 PROCEEDINGS OF THE ACADEMY OF [July, 



Viewed casually, these features appear sufficiently diagnostic. 

 Nevertheless, an examination of the large series of. specimens before 

 me causes me to incline very strongly to the opinion that L. tetra- 

 dynamia will eventually prove to be entirely synonymous with 

 L. japonica, although the differences apparent in the descriptions 

 of the hectocotylized arms and one or two other less important 

 divergencies deter me at present from uniting them. In this regard 

 a comparison of the respective type specimens with one another 

 would certainly prove of the utmost service. 



The present specimens appear to belong beyond dispute to L. 

 tetradynamia, and yet in several particulars Ortmann's diagnosis is 

 not quite sufficient 'to embrace them. The hectocotylus is as de- 

 scribed by Ortmann. Likewise the suckers of the lateral arms are 

 invariably of conspicuously greater size than those of the dorsal 

 and ventral pairs. However, this statement is decidedly not true 

 of both sexes in equal degree, since in all the males I have seen the 

 suckers of the lateral arms are at least half again as large as those of 

 a female of the same size. Other differences to be noted are that 

 the horny rings of the larger tentacular suckers are toothed all 

 round, not alone upon the distal border, with some 23-25 blunt 

 teeth, and that the arms of the third pair are possessed of a decided 

 keel. 



Indeed, the females accord suspiciously well* with the specimen 

 of japonica taken by the Challenger Expedition in the Yokohama 

 Market. The chief points of difference are that here the dorsal 

 arms are distinctly keeled instead of rounded, as stated by Hoyle, 

 and he makes no mention of the great disparity in the size of the 

 suckers, although his phrase "and vary in size in accordance with 

 the arms on which they are situated" may amount to the same 

 thing. Comparison with his excellent figure distinctly fortifies 

 the latter interpretation. Likewise the tentacles are compressed 

 and angular rather than cylindrical, and I have discovered no suckers 

 on the buccal membrane, though I do not regard this observation 

 as proving their absence there. These items of difference, however, 

 seem to be very minor, and were it not for Hoyle's careful description 

 of the curious hectocotylized arm of a male in the Copenhagen 

 Museum which he held to be eonspecific with his type, there could 

 be little hesitation in relegating L. tetradynamia to the synonymy. 



Distribution.— Same, Mutsu (!); Bay of Tokio (type locality, 

 Ortmann, etc. !); Okayama, Bizen (!); Kochi, Toza (Ortmann); 

 Kawatana, Hizen (!). 



