86 



I. IJIMA AND S. IKEDA. 



exist certain discrepancies between Hoyle's description and the specimen 

 in our hand ; but these seem to us to be all such as may not improperly 

 be ascribed either to individual differences or to the different state of 

 preservation. At any rate, in the present state of our knowledge it is 

 difficult to discriminate distinctive points sufficiently material to regard 

 our specimen as specifically different from A. pelagicus. 



The genus Amphitretus was made by Hoyle to constitute by itself 

 alone a distinct family, the Amphitretidoe. It possesses " the character, 

 unique amongst Cephalopoda, of having the mantle fused with the 

 siphon in the median line, so that there are two branchial openings into 

 the branchial cavity, on either side, whence the name." 



In view of this high systematic importance of the genus and of its 

 apparent rarity, we think no apology "is needed for putting on record 

 our observations on the specimen in question, and that perhaps all the 

 less, since Hoyle's type seems to have been in a state much remote from 

 being natural and well preserved. 



Here it may be remarked that the curious octopod with " telescopic 

 eyes," obtained by the " Valdivia " expedition in the Agulhas-Stream 

 and figured, without description, by Chun in his " Aus den Tiefen des 

 Weltmeeres " (p. 535), bears a striking resemblance to Amphitretus in 

 general appearance. In that figure the eye-bulbs are represented as 

 freely projecting while the peripheral gelatinous layer, so conspicuously 

 thick in our specimen while in the fresh state (see Pl. II), is scarcely 

 shown at all. If it be that this condition was brought about by the 

 shrinking of, and perhaps also by a partial damage to, the enveloping 

 gelatinous tissue, it would not be too far going to presume that the 

 " Valdivia " specimen is closely related to A. pelagicus, if not generically 

 or even specifically identical. Professor Chun's forthcoming monograph 

 of the " Valdivia " Cephalopoda will likely contain matters that will 

 settle the question. 



Description of the specimen in the fresh state. 



When the animal was first brought in, it still showed some life as 



