AND THE FISH THEREOF. 23 



multiflora, a representative species of the Boreal form Virgularia mirabilis> 

 a form hitherto strange to the Mediterranean fauna, and altogether to the 

 Lusitanian province. In the same locality are found Alcyonium palmatum 

 and Pennatula phospliorca ; and the Crustacean, GalatJica rugosa, is more 

 prevalent and prosperous here than elsewhere. 



In order to account for the insular appearance of this association of 

 northern representative forms it is necessary to assume that, as elsewhere 

 where analogous appearances of Boreal outliers occur, these forms had a 

 further southern distribution during the Glacial Period, and that in course 

 of time, owing to a raised temperature of the waters, particularly in summer 

 time, their distribution became limited to the deeper and cooler regions, as 

 long as the nature of the bed proved suitable, and the pressure of the water 

 was not too great. 



The Gulf of Fiume, the Quarnerolo, and the Channel of Punta Croce 

 are depressions in the bed to which this theory applies. Further to the south 

 they are shut in from the open sea by a ridge of higher ground, which 

 accounts for their isolation, whilst the lower temperature which prevails 

 on the bed of the Quarnero, and the difference in the composition 

 of the water, due to the limestone springs, must explain why they 

 prosper here, whereas they do not occur in the neighbouring Dalmatian 

 waters. 



Ulterior investigation may possibly bring to light fossil remains of 

 northern forms of Gasteropods and Lamellibranchs, now extinct in these 

 waters. The discovery would go far to explain the phenomenon which has 

 caused this apparent freak of nature, and to furnish the proof of what at 

 present must remain an assumption, viz., that changes of temperature have 

 taken place, which have destroyed some forms of life, whilst others have 

 been able to assimilate themselves to the new conditions. 



Mr. R. Godwin-Austen, in the work, "The Natural History of the 

 European Seas," commenced by Professor E. Forbes, but edited and con- 

 tinued by him, says (p. 157), "the Nephrops norvegicus has its numerical 

 maximum in, and is a good characteristic Crustacean for, the Scandinavian 

 region, but it occurs abundantly in Dublin Bay ; it has not, however, 



