[449] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 155 
those that have been actually taken at the surface will be here 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 jeily-fish, Zima 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 found 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 Jnem- 
iopsis Leidyi, which occurred in abundance at nearly all hours of the 
day and evening, and was very phosphorescent at night; Cyanea are. 
tica, which ocurred chiefly in the day-time, and was here seldom more 
than a foot in diameter; Aurelia flavidula, (Plate XXXVI, fig. 271,) 
which was not unfrequently seen in the day-time; Dactylometra quinque- 
cirra, (Plate XXXVI, fig. 272,) which was quite common both by night 
and day in August and September; and Zygodactyla Grenlandica, (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,’ 
Poronotus triacanthus. 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 often 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 Clupeoid, 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 penalty 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 North American Acalephe, p. 49. 
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