ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 325 
sight, looking over the yacht’s side, was a thing never to be forgotten. 
The sea was swarming with myriads of the Physophora, Diphyes, Cydippe, 
and allies, Cyanea, Aurelia, &e., and long chains of Salpa runci- 
nata. Among the animals observed that evening was a Medusa (using 
that word in a class sense) which was quite unlike any genus that I am 
acquainted with,—a little flat plate, about the size of a threepenny piece, 
with very numerous long tentacles round its edge, the whole animal 
“perfectly transparent and colourless. 
NAKED-EYED MEDUSA. 
Although the following species ought to be incorporated with and inserted 
in their proper places among the preceding Hydrozoa, yet our knowledge 
being at present confined to the gonosome, it is not possible to allocate them 
with any degree of precision. I have thought it better therefore to keep 
them together here, leaving future discoverers, who shall become acquainted 
with the trophosomes, to assign them their respective places. My own 
time in Shetland was too much taken up with other animals to allow me to 
study these Medusoids. The following list contains the species observed in 
Shetland by Forbes, as recorded in his ‘ British Naked-eyed Meduse ;’ but I 
have arranged them more in accordance with our present state of knowledge, 
throwing them into the families and genera to which they are referred by 
Prof. L. Agassiz in his ‘ Contributions to the Natural History of the United 
States,’ vol. iv. 1862, and by his son, Alexander Agassiz, in his ‘ Illustrated 
Catalogue of North American Acalephe,’ 1865. 
Order THECAPHORA, Hincks. 
Fam. Ocraninpa@, Esch. 
Genus PLarypyxts. 
Thaumantias ceronautica, Forbes. ‘‘ Off Bressay, and in Hamna Voe in 
Papa” (Forbes). 
maculata, Forbes. ‘Sound of Bressay, but not plentiful ” (Forbes). 
Not hitherto observed elsewhere. 
globosa, Forbes. ‘“ Very abundant in the harbours on both sides of the 
Shetland Isles ” (Forbes). Not as yet noticed elsewhere. 
melanops, Forbes. ‘Has hitherto occurred only in the Zetland seas, 
and is not very common there ” (Forbes). 
L, Agassiz considers the above four species to be referable to Pla- 
typyais, I. Agass., or the closely allied genera Clytia, Lamx., or 
Wrightia, L. Agass. ; but the younger Agassiz subsequently writes (Cat. 
North Amer. Acalephe, p. 103), “ may not the 7’. gibbosa of Forbes be a 
young Halopsis? They resemble the young of this species (Halopsis 
cruciata, A. Agass.); also 7’. globosa, and perhaps 7. pilosella.” 
Genus Ocranta, Pér. & Les. (restricted). 
Thaumantias hemispherica, Forbes. ‘“ Zetland, where they abound in the bays 
and harbours” (E. F.). This species is considered by L. A. to be synony- 
mous with Oceania phosphorica, Péron & Les. and the 7’. inconspicua, T. 
lineata, T. punctata, T. pileata, and T. Sarnica are said to be probably 
different stages of growth only of 7. hemispherica. 
lineata, Forbes. ‘Taken in the Zetland seas in 1846, but not found 
common ” (E. F.). 
convexa, Forbes. ‘ A very common species in the Zetland seas ” (E. F.). 
“ May be a distinct species ” (L. A.). 
