INVERTEBRATE ANIMxiLS OF VINEYARD SOUND, ETC. 449 



those that liave been actually taken at the surface will be liere included. 

 Quite a number of the species were not observed by us, but have been 

 recorded by Mr. A. Agassiz, but in some cases he has given neither the 

 time nor date of capture. 



A fine large specimen of the beautiful jelly-fish, Tima formosa, has 

 been sent to me by Mr. V. N. Edwards, who captured it at Wood's 

 Hole, April 30. He states that the same species was very abundant in 

 February, 1872. It has not been previously recorded as fcfund south of 

 Cape Cod. The specimen received differs from the description given 

 by Mr. A. Agassiz, in having thirty-six tentacles instead of thirty-two. 



Among the most common of the larger species in summer were Mnem- 

 io2ms Leidyi, which occurred in abundance at nearly all hours of the 

 day and evening, and was very phosphorescent at night; Cyanea arc- 

 tica, which ocurred chiefly in the day-time, and was here seldom more 

 than a foot in diameter; Aurelia flavidida^ (Plate XXXYI, fig. 271,) 

 which was not unfrequently seen in the day-time ; Dactylometra quinciue- 

 cirra, (Plate XXXYI, fig. 272,) which was quite common both by night 

 and day in August and September; and Zygodactyla Grcenlandioa, (Plate 

 XXXVII, fig. 275,) which was common in July, both in the day and 

 evening, but was seldom seen later in the season. 



The two species last named, and also the Cyanea arctica^ were fre- 

 quently found to be accompanied by several small fishes, of different 

 sizes up to three inches long, which proved to be young " butter-fishes,' 

 Foronotus triacanthtis. These fishes swim beneath the broad disk of 

 these jelly-fishes, surrounded on all sides by the numerous tentacles, 

 which probably serve as a protection from larger fishes that are their 

 enemies, for the tentacles of the jelly-fishes are capable of severely sting- 

 ing the mouths of most fishes, evidently causing them great pain. As 

 many as ten or twelve of these fishes were oiten found under a single jelly- 

 fish, and in one case twenty-three were found under a Cyanea about ten 

 inches in diameter. They do not appear to suffer at all from contact with 

 the stinging-organs of the tentacles, and are, perhaps, protected from them 

 by the thick coating of tenacious mucus which constantly covers the skin, 

 and gives them their common English name. Mr. A. Agassiz states* 

 that he constantly observed a '' Clupeoid '" fish under the Dactylometra 

 in this region, which had essentially the same habits, according to his 

 account, as the species observed by us^ though, if a Clui)eoid, it must 

 have been a very different fish. 



He says, however, that the fishes observed by him were occasionally 

 devoured by the jelly-fish : ^' It is strange that the fish should go there 

 for shelter, for every once in a while one of them pays the penal t}' by 

 being swallowed, without this disturbing the others in the least ; they 

 in their turn find food in the lobes of the actinostome, and even eat the 

 folds themselves, until their turn comes to be used as food. I have 

 seen in this way three fishes eaten during the course of as many days. 



* Catalogue of Nortli American Acalepliie, p. 49. 



S. Mis. 61 29 



