Januaiy, 1921] 



The Canadian Field-Naturalist. 



of France; Mediterranean and Black Sea; 

 Atlantic coast of the United States, in- 

 eluding the Woods Hole region; Australia 

 and the Philijopine islands. Its important 

 synonyms are P. agassizii Claparede 1868, 

 and P. Uttorea Verrill 1873. 



On the sliore between the Biological Sta- 

 tion and Joe's point at low tide it is very 

 abundant on the shells of the living whelk, 

 Buccinum undatum. The free-swimming 

 larvae are quite common in the bay, thus 

 swelling the nutritive value of the plank- 

 toiL Tlie mud-tubes of the worms project 

 from openings in the surface of the shell 

 and when they are cleaned away the latter 

 is found to be eroded with vermiform 

 grooves. Often the worms are not buried 

 in the shell but lie in its furrows, and they 

 occur also elsewliere in tlie mudd}^ crevi- 

 ces of rocks. Tliey are not found at or 

 near the mouth of the shell. The same spe- 

 cies causes the so-called "worm-disease of 

 oysters" in New South Wales (White- 

 legge) and in the Mediterranean (Carraz- 

 zi), but when it infests oyster beds it at- 

 taches itself at the margin of the valves 

 where it causes eventually a fatal accu- 

 mulation of mud. Another species has 

 l)een found in company with P. ciliata, 

 namely, P. hoplura, which actually excava- 

 tes galleries in the shell of oysters, but it 

 is not certain whether this is effected by 

 mechanical or chemical means. It is pos- 

 sible that P. hoplura may also occur at St. 

 Andrews but it has not been recorded yet. 



In frequenting the shell of such an act- 

 tive gastropod as the whelk, the Pohjdora 

 derives advantage from its mobility, like 

 Hydractinia which commonly selects sliells 

 occupied by Hermit Crabs but has been 

 found upon the shell of a living Buccinum 

 nndatvm at Woods Hole, as well as upon 

 rocks and piles. Tlie frequency of the oc- 

 currence of Pohjdora upon Buccinum at 

 St. Andrews entitles it to the local appella- 

 tion of " whelk- worm. " 



Lepas hillii Leach. 



No Lepadidae are native to the bay, such 

 as do occur being found only on drifting 

 wood that has l)een brought in more or less 

 casually from the warm waters of the Gulf 

 Stream, where the genus Lepas occurs com- 

 monly in several species. There is no re- 

 gularity in their entrance into tlie bav. In 



1912 a block of Avcod with a large number 

 of Lepas hillii attached and well perforat- 

 ed by the shipworm, Teredo,^ which is also 

 an alien here, was brought to the Station 

 by fishermen, who had found it floating 

 beside a weir near St. Andrews. On 

 August 17th of tlie present year there were 

 sent to the Station specimens of the same 

 species that had been taken by a fisher- 

 man from a floating lobster pot near the 

 mouth of Kitty Cove. In both cases the 

 fishermen considered these animals as 

 something quite new and unheard of, 

 which indicates their great rarity here. 



Idothea metallica Bosc. 



When the late Mr. N. A. Wallace was 

 making his study of the Isopods of the Bay 

 of Fundy (recently published) in the years 

 1912 and 1913, he did not find this species. 

 Last summer (1919) during the investi- 

 gation of St. Mary bay on the coast of Nova 

 Scotia by the Biological Vessel "Prince'', 

 Dr. Philip Cox found a single specimen of 

 this form in the bay. Subsequently we ob- 

 tained a number of individuals from float- 

 ing seaweed on our way across the Bay of 

 Fundy. A large individual was taken in 

 the St. Croix river from the wharf of the 

 Biological Station by Dr. F. S. Jackson in 

 July of the present year. This species is 

 an inhabitant of the Gulf Stream, where 

 it occurs on floating Sargasso weed. It 

 does not properly belong to our coast, its 

 presence indicating some drift in to the 

 coast from the waters of the Gulf Stream. 



Cancer horecdis Stimpson. 



The common crab of the bay is Cancer 

 irrorafus Hay, the rock crab, which is to be 

 found nearly everywhere on sandy and 

 gravelly or stony bottoms from low-water 

 mark out into deep Avater. At the mouth 

 of the bay on rocky shores exposed to the 

 waves of the Bay of Fundy the Jonah crab. 

 Cancer horealis, is to be found quite reg- 

 ularly in small rock pools and in crevices. 

 This latter species is about the same size 

 as the rock crab (up to 12 or 13 cm.) but 

 is rougher and more strongly built. In the 

 St. Croix river in the vicinity of the Sta- 

 tion dead individuals have been found on 

 two occasions, namely in 1913 and again 

 during the present summer. It was a 

 matter, therefore, of considerable interest 



