DoO REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



We can, thereforej predict that here we may look for medusse with 

 a direct developmeut, or at all events for those with au unattached 

 yoimg. We know too little of tlie embryology of different genera 

 of medusae to get together enough facts to throw much light on this 

 question. It is among those genera with which the deep-sea Acraspeda 

 liave their closest likenesses that we find a direct development, but 

 late researches have shown that even some of the highest also skip the 

 Sci/phostoma stage, and have a development more like that Avhich is 

 called direct. The so-called deep-sea medusaj seem to me to indicate 

 that the mode of developmeut known as direct is the primal condition, 

 and that the growth in which an attached form enters the series is a 

 secondary modification ; but they certainly do not prove such to be 

 the case, and I doubt whether we can demonstrate it as far as they are 

 concerned until the bathymetrical limits of their habitat is known. 



The material used in the preparation of this paper was sent me by 

 my esteemed friend, Prof. A. E. Yerrill. It is a xdt^asure to acknowl- 

 edge this indebtedness. I am also indebted to Mr. R. Rathbun for 

 several interesting specimens, also collected by the Albatross. Many 

 of these are from the Caribbean Sea and Gulf of Mexico, and will be 

 mentioned when the collections from these regions are worked over. 

 The present report considers the medusa? of the Gulf Stream region 

 from Florida to the latitude of George's Banks. 



ACRASPEDA, Gegenbaur, 1856. 



Family PERIPHYLLID^, Haickel, 1877. 



Periphylla, Steenstrup. 



The genus PeripJiylla appears to be common in the waters of the 

 Gulf Stream. It was first found in American waters by Smith and 

 Harger over George's Bank,* and a brief notice of it was published in 

 the Tram. Conn. Acad., ]874.t In 1880 the Blake collected the same 

 genus| otf Cape Ilatteras {BkJI. Mus. Comp. ZooL, vol. viii, iSTo. 7). 

 In the report on the Acalephs collected by the United States Fish Com- 

 mission in 1880-'81, P. hyacintliina, St., is recorded from the several 

 localities mentioned below : 



station. Locality. 



Olf Mai'tha's Vineyard : 

 936 I S. by E. * E. 104A miles, surface. 

 952 S. i E. 87* iiiil.'s, .surf:i(!e. 



954 S. J E. 91'miles, suifMi-o. 



995 SSW. I W. 104i miles, surface. 



The genus PeriphyUa is represented in the collection of 1883-'84 by 

 many specimens, which differ so mucli in outward appearance, in color 



*It8 most northern observed liinit on our oast coast. 



tThe medusa referred to I Carybdea perijihiilla is the same as P. hjacinthina, St. 



ITlie ixjetluef^ referred to JJodicahostrucha duUa, Brandt, is P. hyacinthina, St, 



