100 



I. I.TIMA AND S. IKEDA. 



placed too close together). Through the visceral membrane is visible 

 the terminal thickened portion of the oviduct. This runs from the 

 external opening laterally and nearly horizontally for about 5 mm., then 

 to bend backwards and mediad but soon to make a globular swelling, 

 whence posteriorly the oviduct can be seen as a fine thread for a short 

 distance before it becomes lost to the sight. On the dorsal aspect of the 

 visceral sac (Woodcut 3), both oviducts are seen to emerge from the 

 deep parts and to unite, right over the systemic heart (*. /(.), into a very 

 short unpaired duct which soon joins the oval-shaped ovary (pv.), 

 situated just behind the stomach (st.). 



For all the other visceral organs shown in Woodcuts 1 and 2, we 

 consider no special remarks are needed. 



The gills, 18 mm. long, have alternately arranged, convoluted 

 lamellte, about 10 in number on each of their sides. The branchial 

 artery (b. a.) is thick and fleshy ; its surface, like that of the branchial 

 hearts, is sprinkled with chromatophores. It is suspended from the 

 mantle by a thin, mesentery-like band (g. s.), which is traversed across 

 by a number of fine muscular bundles. 



It will be seen from the above cursory account, as well as from the 

 woodcuts given, that the arrangement of the organs in the mantle sac is 

 essentially as in Octopus and related forms. In no less degree does it 

 show resemblance to that of Alloposus pacificus. 



Affinities of Amphitrelus- 



As regards the affinities of the genus, Hoyle assumed it to be most 

 nearly allied to Cirrotexdhis, as agreeing with each other in having the 

 suckers arranged in a single row and the arms united by a broad web. 

 We greatly doubt if these points of agreement taken alone can be of 

 much weight in determining the affinity, especially in the presence of 

 such important differences as were pointed out by Hoyle himself, as, for 

 instance, the absence of cartilage, of fins and of cirri in Amphitretus. 



