NOTES ON AMPHITRETUS. 



93 



suppose that in Tremoctopiis or in Alloposus a fusion took place at the 

 buttons as well as inedianly frani these between the mantle-edge and the 

 ventral funnel-wall, much the same condition as that seen in Am- 

 phitretus will be the result. 



The siphon in the preserved specimen is a flatly compressed tube, 

 measuring about 28 mm. in length. It is 22 mm. broad at base and 

 narrows anteriorly to a breadth of 9 mm. It lies flat on the umbrella, 

 is covered over by the common skin and extends forwards for about 

 one-third of the distance between the mantle-edge and arm-tips. The 

 lateral edges are vaguely visible through the skin. The external 

 opening is transversely slit-like, about 7 mm. long and bordered by 

 somewhat prominent lip-like edges. The flat shape of the siphon may 

 in a measure be due to the artificial compression. The head is indis- 

 tinguishable from the body, being indicated only by the eyes. It is 

 anyway small, that is to say, if we leave the outer gelatinous envelope 

 out of consideration ; otherwise it may be called large, being as broad as 

 the body. Just the same condition obtains in Alloposus pacifiais. 



So far as could be ascertained by feeling from outside, we are 

 inclined to assume the absence of a cephalic cartilage or of any other 

 cartilage in the entire body. We have also failed to discover aquiferous 

 pores. 



The eyes are nearly pear-shaped with spheroidal base and rounded- 

 conical outer end. They are about 13 mm. long. The bulbous base, 

 about 10 mm. in diameter, is in its outer half studded with chromato- 

 phores on a dark back-graund ; the inner half is of a lighter color. The 

 outer rounded-conical or nearly hemispherical portion of the eye-bulb, 

 about 6 mm. in diameter at base and not more than 3-£- mm. in height, 

 is encircled basally by a light-colored zone and in the pupilar end by 

 another zone of a dark brownish color. The latter incloses a whitish 

 looking pupil of 1-|— 2 mm. diameter. The two eyes are in contact with 

 each other in their broadest portion. Their axes somewhat diverge 

 outwardly and are at the outer end 12 mm. apart from each other. 

 Between the eyes and over their contact point, there are seen two rather 



