DE. m'iNTOSH OIT BEITISH SALP^. 43 



alive for several days, provided tlie vessel was clean, wide at the 

 top, and the sea-water frequently renovated. 



No large Medusae occurred in the bay at this date, the only 

 other oceanic swimmers being hosts of a little Sarsia and a Thau- 

 mantias, that were caught in the creeks. 



The Salpse seem to be very sensitive in regard to the weather, 

 as indeed the fragility of their chains might indicate. None 

 appeared for about a week of rough or rainy weather, even though 

 the surface of the sea might be as smooth as glass but for the 

 pattering of the rain-drops. On a somewhat rough day the 

 dredge near the mouth of the loch brought up in its progress 

 hosts of the little Thaumantias previously mentioned, but not a 

 single Salpa ; so that they must have entirely evacuated the bay. 

 Towards the eighth day a few isolated individuals were met with, 

 not in the best condition ; those amongst the rocks were mostly 

 withered ones floated off the blades of Euci between tide-marks. 

 About a fortnight afterwards many of the same species {S. run- 

 cinatd) were got near the mouth of the bay ; but, curiously enough, 

 all were brought in by the dredge, not a single specimen being 

 captured by the towing-net, although the sea was moderately 

 calm. Two other forms, however, were abundant on the sur- 

 face, viz. Salpa spinosa of Otto (figured and described by Sars*, 

 and mentioned by Forbes and Hanley in their work) and its 

 progeny in chains (figs. 5 to 9). None but battered specimens 

 of 8. runcinata appeared at this time near the shore. 



The enormous numbers of the two forms of S. spinosa that were 

 driven into the creeks next day by the easterly breeze were sur- 

 prising, and showed the extraordinary fecundity of the genus. 

 The hand could not be held amongst the mild sea- water that laved 

 the littoral Fuci without coming into contact with chains of the 

 one form and individuals of both, that every wave of the sea 

 poured in to be destroyed. . After the breeze moderated, the Fuci 

 between tide-marks sparkled in all directions with the quivering 

 bodies of the unfortunate Salpge, that, besides, here and there lay 

 in heaps where the ebbing tide had stranded them behind stones. 

 The hand net was filled by a solid mass when plunged into the 

 water, and only a few specimens of S. runcinata were found 

 amongst them. 



* ' Fauna littoralis Norvegise,' part i. p. 79, tab. 10. This work did not 

 come into my hands before the present paper had left them. The differences in 

 the figures and descriptions will explain themselves ; they are chiefly confined 

 to the former. 



