54 TRACHYNEJIID.E. 



margin of the circular tube (Fig. 72), while at other times it is closely 

 hemmed in on all sides. (Fig. 73.) The base of the tentacles swells 

 out above and below the chymiferous tube, forming a large bulb, in the 

 upper portion of which pigment-cells of a brownish-red color (Fig. 73, m) 

 arc loosely scattered, while in the lower portion (Figs. 74, 75, j)") ^ 

 dark concentrated pigment-spot is found. The tentacles are hollow, 

 and are surrounded for their whole length by clusters of lasso cells 

 (Fig. 75, I) similar to those of young Tulndarian MedusEe, such as 

 Coryne and Syndiction. 



The size of this Medusa is about one twentieth of an inch in diameter. 



Found at Nahant, September, Alex. Agassiz. 



Museum diagram No. 16, after Alex. Agassiz. 



^GINOPSIS Br. 



^(/inopsis Br. (non J. Miiller). Prod. Mem. Acad. St. Pctersbui^, p. 222. 1835. 

 jEfjinopsh Agass. Cont. Nat. Hist. U. S., IV. p. 170. 1862. 

 yEijinopsis Less. Zooph. Acal., p. 304. 1843. 



.ffiginopsis Laurentii Br. 



^ginopsis Laurentii Br. Mem. Ac. St. Petcrsb., PI. G, p. 363. 1838. 



JEijinopxis Laurentii Less. Zooph. Acal., p. 304. 1843. 



yEyiniipsi.'i Laurentii Agass. Cont. Nat. Hist. U. S., IV. p. 170. 1862. 



Laurent Bay, Beliring's Straits (Mertens). 



Suborder TRACHYNEMID^ A. Agass. 



Forbes, in his Natural History of the British Naked-eyed Medusa?, 

 characterized as a family the Circeidaa ; at that time only a few other 

 species of this group were knowm, but so imperfectly described that 

 even at the present day the natural affinities of these Medusa? are far 

 from being well ascertained. Gegenbaur, who has studied Medusiu 

 which I suppose to be only the young of closely allied forms, has also 

 separated his young Medusa? as a distinct family, under the name of 

 Trachynemida\ The Diau art couica of Lesson ma}^ even prove to be 

 the adult of his Trachi/nema cUiatum, as it is evident from the draw- 

 ing of Lesson* that he has figured there a Medusa closely allied to 

 Circe Forbes, and perhaps identical with it. A comparison of Trachtj- 

 nema ciliafttm {Ocg. PI. IX. Fig. G) with the young specimens of Circe 

 here figiu-ed, will show the close affinity of these two Medusa\ The 

 fiunily name of Trachynemidai ought therefore yield to that proposed 



* Anu. Scicn. Nat., Vol. X. I'l. 6, Fig. 3. 



