MUSEUM OF COMPARATIVE ZOOLOGY. 81 



above, in having eight otocysts and the same number of rudimentary tentacles 

 alternating -with them on the bell margin. The marginal lappets, instead of 

 beino' long and pointed, as in the above Ephyra, are rounded, and almost oval 

 in contour. The tentacles are very short, resembling little buds in the interval 

 alternating between the marginal bell lappets. 



The youngest Ephyra of Linergcs which was taken is much younger than any 

 yet figured. The umbrella has a disk-like form, is flat, and has a coloration 

 similar to that of the adult. It was not traced into a larva like that which is 

 elsewhere* doubtfullv described as the young of L. Mercurius. 



Agalma Okenii Esch. 



Several specimens of .4. Ohenii^ were collected in Castle Harbor. This 

 species has never before been taken on this side of the Atlantic. A. Okenii 

 resembles our common Agalma, A. elegans F., but is easily distinguished from 

 it by the rigid character of the body and the thickness and peculiar form of the 

 covering-scales. 



The axis in larger specimens is about three inches long, and has little flexi- 

 bility. The polyp stem, or that part of the axis which bears the polypites and 

 their covering-scales, is almost straight, and on account of the thickness and 

 .close approximation of the covering-scales is never thrown into those curves 

 which impart so much grace to the Agalma when in motion. The color of the 

 axis is vellow and orange. The float and axis resemble in most of their exter- 

 nal features the same structures in Agalma. The swimming-bells are similar 

 to those of .4. -papillosum F. in possessing blind extensions of the bell cavity 

 into the gelatinous horns which arise on either side of the attachment to the 

 axis and embrace the stem. 



The covering-scales are very thick, and stand out at right angles to the stem 

 at their points of attachment. In looking at the Physophore from the side, it 



was not successful in my searcli for it. Cassiopea has sixteen sense-bodies, and in 

 that respect differs very widely from niiDst Discophora. In one or two other gen- 

 era, as Collaspis and Alolhi, there are more than eight marginal sense-bodies, but the 

 difTerences between these genera and the Ephyra mentioned seem too. great for a 

 reference of it to them. 



If my Ephyra is in reality the young of Cassiopea, or some other genus with like 

 sedentary habits, it furnishes us with the interesting fact, whicli I have long sus- 

 pected, that in its younger larva? Cassiopea is free-swimming, and has embryonic 

 tentacles in the Ephyra which are lost in the adult. 



* Bull. Mus. Comp. ZoJU., Vol. IX. No. 7. 



t This species of Agalma closely resembles Crjjstallodes rigidum Haeck., witli 

 which it is probably identical. It seems also to be the same as a Siphonophore 

 described by Gegenbaur, from the South Atlantic, lat. 2° S., long. 26° W. (Neue 

 Bcitrage zur naheren Kenntniss der Siphonophoren). I have followed the latter 

 author in considering it the same as the Agalma Okenii described by Eschscholtz, 

 from the North Pacific Ocean. 



