[11] 



MEDUSAE FROM THE GULF STREAM. 



523 



POLYCANNA AMERICANA,* FewkeS. 



Of all the specimens of the species examined in the collection of 1885, 

 No. 11674, station 2503, is the best preserved. A diagnosis of the spe- 

 cies is made from this specimen. 



Disk flat, with a slight apical protuberance. Eoof of the stomach 

 convex, thicker than the margin. Diameter of the roof of the stomach, 

 28 mm . Diameter of the disk, 70 mm . Stomach wide, lips open. The 

 stomach wall is formed by papillate folds, the number of which is equal 

 to the tubes. These tubes fall down below the velum. Numerous (107) 

 chyiniferous tubes, each of which bears a folded sexual gland, reaching 

 from the vicinity of the stomach to the marginal vessel. 



Tentacles, 29-32? in number, long, base inflated. Between each pair 

 of tentacles there are five or more small protuberances on the bell mar- 

 gin. These are either otocysts or immature tentacles. No subumbral 

 tubercles on the umbrella, between the chymiferous tubes. 



Of the other recorded Polycamiw, P. grcenlandica, P. flava, and P. 

 crassa have more tentacles than chymiferous tubes. No tubercles are 

 recorded in P. flava. In an alcoholic specimen of Zygodactyla, with 

 tubercles, now in the collection of the Museum of Comparative Zoology, 

 the tentacles are missing. I cannot, therefore, say at present whether 

 the specimens with tubercles have the same number of tentacles as 

 tubes or not. If the Zygodactyla, with tubercles, last mentioned, has 

 more tentacles than tubes it may be grcenlandica; if less, it is doubtful 

 whether it is the same as the species {grcenlandica) which is recorded 

 by A. Agassiz as possessed of more tentacles than tubes. 



Family AMPHINEMID^E, Hreckel. 



STOMATOCAf PERIPHYLLA, Hseckel. 



Two well-preserved specimens of this species were found by the 

 Albatross in the summer of 1886. 



We have in our waters two very beautiful genera of the family of 

 Tiaridse, with two opposite tentacles. One of these is the well known 



* This species is supposed to be the same, or closely allied to the genus once called 

 Ehegmatodes, now Polgcanna. It is given the former name in the plates, the latter 

 in the text of Haeckel's System der Medusen. The species falls in Hoeckel's subgenus 

 Ehacostoma (L. Agassiz, sensu rhutato) and may be the same as P. fungina, Haeck. 



t The spelling, Stomatoca, is adopted instead of Stomoloca, from the derivation 

 6r6/.ia (gen. dr'ojuaroS) root 6ro/uav. 



