DESCRIPTION OF 0PI8TH0 TEUTHIS DEPRESS A X. SP. 3^7 



our «pccimen the left fin is shrunk mikI smaller than the other, 

 evidently owing to careless handling wlien fresh, llie right tin is 

 Avell preserved, rather thick and triangular in sliape, being aljout one 

 and a half times as 1)road (transversely) as it is long. The free apex 

 is rounded and of the two edges, the anterior is somewhat more 

 arched than the posterior. The shape, however, is likely subject to 

 chanu'es, accordino^ to the different state of contraction of tlie internal 

 tissues, as the fins are very soft structures containing no supporting 

 elements whatever, Nevertheless, on raising them from tlieir natural, 

 laterally directed position and then releasing tliem. they return to the 

 original position of their own acc(jrd. The [)lace of their attachment 

 is close behind the eye-bulbs, the distance between the middle of the 

 fin-base and the eye-opening being about one fifths of the distance of 

 the former from the branchial aperture. Moreover, the fin-base is 

 situated more to tlie middle than the eye-opening, while the fin 

 itself extends laterally but a short distance beyond the same. 



The branchial aperture is a small crescent-shaped opening, situated 

 at a distance frcjm tlie free edo-e of the dorsal web about four times as 



a 



great as that from the ventral web. It })artially embraces the siphon, 

 which, so far as it shows itself outside the branchial aperture, is of 

 very insignificant size, Xo p-art of it can be said to be freely project- 

 ing beyond the surface of the ventral web and its presence is only 

 re^■ealed by a slight prominence and by the existence of a small, 

 transversely slit-like siphcmal opening close behind the Ijranchial 

 aperture. 



As alreadv mentioned, the inner or inferior surface of the umbrella 

 (tig. o) is plane. The arms do not project al)Ove it. except very near 

 the tips, where the webs becoming thinner and ie)ld-like, join them on 

 their upper sides. The skin is tolerably firmly attached to the inner 

 surface ot the arms, as a result of the fact that there is interposed on 



