belonging to the Family Laodiceidas. 473 



Expedition (S.S. ' Scotia ') in Stanley Harbour, Falkland 

 Islands. A description of it, with figures, will be given in 

 the Report on the i\ledusa3 collected by the expedition, to be 

 published in the ' Transactions of the Royal Society of 

 Edinburgh.' 



It is very much like S. laciniata, but has a series of long 

 tentacles and a series of very short rudimentary tentacles. 



Genus Ptychogena, A. Agassiz, 1865. 



Generic character. — Laodiceidfe with four radial canals; 

 with a central stomach and mouth ; with the basal bulbs of 

 the tentacles without ocelli. 



Ptychogena lactea, A. Agassiz, 1S65. 



Ptychogena lactea, A. Agassiz, 1865, p. 1-37, figs. 220-224 ; Haeckel, 



1879, p. 147 ; Hargitt, 1905, p. 45. 

 Ptychogena pinnulata, Hfecliel, 1879, p. 148 ; Hsecljel, 1882, p. 7, pi. ii. ; 



Gronberg, 1898, p. 465; Leviusen, 1892, p. 1J5. 

 Ptychogena pmnulata, var. intermedia, Linko, 1904, p. 217. 



This species was first discovered by A. Agassiz, who found 

 it abundant for a few days in Massachusetts Bay, about 1864, 

 and it has not again been recorded for the North-American 

 coast. This single record rather indicates that this medusa is 

 not a native of that region, but has probably drifted down 

 south from the Arctic regions. 



According to Hseckel P. innnuJata differs from P. lactea in 

 the shape of the gonads. Those of the latter have fewer 

 lateral diverticula, but some of the longer ones are slightly 

 branched. 



Linko has found in Barents Sea a form which he considers 

 to be a variety intermediate between P. lactea and P. pinnu- 

 lata. This variety has gonads shaped like P. lactea^ but with 

 about as many diverticula as P. pinnulata. It agrees in 

 colour with P. lactea. I do not think that the differences in 

 the shape and size of the gonads are, taken by themselves, 

 sufficient for a specific character, and Linko's variety shows 

 a connexion between the two species. The differences in shape 

 and size are more likely due to the development of the gonads. 



This species is ])robably a scarce Arctic medusa which 

 drifts south into the North Atlantic. There is no trustworthy 

 evidence that it is a deep-sea form. 



Distribution. Arctic Ocean: Greenland [Gronberg). Barents 

 Sea (Liuko). North Atlantic : America, Massacliusetts Bay 

 and Nahant (A. Agassiz). Iceland {Levinsen). Between 



Ann. (fe Mag. X. Hist. Ser. 7. Vol. xx. 31 



