tVie characters of both the Loptolinae and Ti-achylinas , hav- 

 ing T,he ocelli of the former order and the chitinous p:orran- 

 gium containinp; the developing medusa buds, (A.":assiz, 1865, 

 p. 12j) wiiile Professor Bi-ooks has demonstrated (lo9r;) that 

 it also possesses the true endodermal sense-clubs of the 

 Trachylinae. 



It may bo that the present record of obsei'vations on 

 Gonionema will be of intei-est as contributing some new 

 points to the present meagre knowledge of the manifold 

 forms and types which are exhibited in the development pro- 

 cesses of this great gi-oup, 



I. GONOSOME . 



Gonionema is a very attractive feature of the 

 Woods Hole fauna. Its exquisite glassy umbrella, marked 

 with a cross of yellow or brown by the four radial canals 

 and the gonads, a brilliant row of closely set spots of 

 gleaming phosphorescent green outlining its edge, the 

 fringe of delicate streaming tentacles strung with bead- 

 like clusters of thread cells, are all more or less famil- 

 iar to many American biologists (Fig, 1), On cloudy days 

 or toward nightfall it is very active, swimi^iing upv/ard to 

 the top of the water and then floating back to the bottom. 



