PRELIMINARY NOTE ON THE LIFE-HISTORY 



OF GONIONEMUS. 



LOUIS MURBACH. 



The occurrence of large numbers of a striking and beautiful 

 medusa at Woods Holl, during July and August, presented a 

 favorable opportunity for studying the life-history of a form, 

 only the adult stage of which is known. When it was found 

 to be Gonionemus, discovered by A. Agassiz, in 1862, in the 

 Gulf of Georgia, Washington, and, as far as I can find, not 

 further described since then, I determined to follow out its 

 development.^ 



It seems desirable to give a preliminary account of results 

 up to this time, as the completion of the work may have to be 

 put off until next year on account of the present scarcity of 

 the medusae. 



Agassiz's^ diagnosis is as follows: Gonionemus, A, Agassiz, 

 "The spherosome is an oblate spheroid, cut from pole to pole; 

 the ovaries are in lobes alternating on the sides of the chymif- 

 erous tubes, and extending their whole length, from the diges- 

 tive cavity to the circular tube; the digestive cavity is long 

 and very flexible ; the tentacles are numerous, large, and 

 exceedingly contractile; chymiferous tubes are four in num»- 

 ber." "Found in July, Gulf of Georgia, W. T., 1862." 



In his species description he brings out other features 

 for recognizing the medusae. Such are the violet color of 

 the lobed ovaries, a spot of the same color near the tip of 

 each tentacle, and the fact that the tentacles are kneed at the 

 end (serving to fasten the animal to sea-weed by means of 



i For working facilities at the Fish Commission Laboratory during this sum- 

 mer, I am greatly under obligation to the Commissioner of Fish and Fisheries. 

 Also to Dr. C. O. Whitman, the Director of the Marine Biological Laboratory, 

 for use of library, etc. 



^ Illustrated Catalogue of the Museum of Comp. Zool. Harvard Coll., No. ii, 

 North Am. Acalaphae. 



