AMERICAN NATURALIST. 



Vol. xvi. — FEBRUARY, 1882.— No. 



THE SIPHONOPHORES. 



BY J. WALTER FEWKES. 

 {Continued from October number, 1S81.) 

 IV.— ANATOMY AND DEVELOPMENT OF DIPHYES. 

 'THE Siphonophores which we have thus far considered all 

 A agree in this particular, that they have a float attached at one 

 end of the stem to buoy it up in the water. It may, in some 

 genera, be doubtful how far this structure is necessary, or to 

 what extent it is functional, but it is never without representation 

 in any of the Physophoridae. We come now to consider tubular 

 jelly-fishes, which may be looked upon as in many respects the 

 highest 1 of the Siphonophores. In no member of the group is 

 there a float such as is to be found in Agalma and its allies, while 

 in details of structure their organization is very characteristic, and 

 different from the tubular Medusae already studied. A good 

 representative of these Medusae, whose several genera make up 

 the Diphyidae, 2 is the beautiful genus Diphyes, represented in our 

 waters, as far as explored, by a single species. An account of 

 the anatomy and development of this genus seems a fitting intro- 

 duction to a more extended acquaintance with, the remaining 

 Siphonophores, which embrace some of the most beautiful ani- 

 mals with which the student of marine life is familiar. 



The differences between Diphyes and Agalma seem so great 



fa to the primitive medusa of Agalma, we' may place them, as a whole, below the 

 Physophoridie. My reasons for ]>Luin<' them h.-hei will W given later in tins 

 paper. 



""The designation Diphyidsc seems to me preferable to Leuckart's term, Calyco- 

 phorid*. Theve.y.d „ ,^ (1|1 | ,,,, |( , 1 V ,. the type of a family between the 

 Physophorid* and Diphvid.v. 



