79 



NOTES ON THE FAUNA OF FALMOUTH FOR 1900. 

 By RUPERT VALENTIN. 



On glancing over my note-books kept dviring the past year, 

 I have failed to detect the record of anything of great interest 

 beyond the ordinary seasonal changes in the plankton. Taken 

 as a whole, the year 1900 did not come up to the average, in 

 spite of the fact that the early months were unusually mild. 

 During July, August, and the first half of September, the 

 average surface temperature of the sea was very low ; and this 

 accounts for the exceptional scarcity of all pelagic forms, and the 

 almost entire absence of oceanic visitors. During the early 

 portion of the year the prevailing winds were from the S.W.^ 

 and as a natural consequence the usual invasion of warm water 

 from the Atlantic followed. This exceptional warmth acted as a 

 stimulus on the littoral fauna, many nudibranchs being detected 

 depositing their ova on the sides of the coal hulks moored 

 in the inner harbour during the commencement of January. 

 About this time I noticed that those hulks which were 

 moored by one or two cables from the bow, and so were able to 

 swing with the tide and wind, invariably had a good representa- 

 tive fauna on the port side ; which, owing to the prevailing winds, 

 would be exposed to the southward and so enjoy all the additional 

 heat and warmth caused by the sun's rays. The starboard sides 

 of these hulks which faced the northward had but little life on 

 them. In one instance, an ice- hulk was moored by four cables : 

 two from the bow, and two from the stern, so that she was held 

 fast facing the East. In this instance the starboard side was 

 crowded with animal life and sea-weeds, and the port side only 

 sprinkled with barnacles (Balanus balanoides). It should be 

 noted that all these hulks are usually beached at least once a 

 year to have their sides scraped and afterwards to receive a coat 

 of tar or pitch extending to a short distance above water-line. 

 This black colour forms a splendid heat-absorbing surface, a 

 fact discovered long ago by the nudibranchs, which flock thither 

 to deposit their ova in so favorable a locality. During a warm 

 summer's day it is by no means unusual to see the pitch in a 



