6 
On the outer side of Bliss Island, among the sea-weed on the ledges, the 
mussels were quite abundant. Also on the sheer rocks forming a large portion 
of the shore patches of mussels were found to occur quite extensively in a strip 
from two to four feet wide just above low-water mark. In Fisherman’s Cove, 
on the inner side of the island, mussels were found growing on the muddy, 
gently sloping shore. 
On Deer Island, from Northern Harbour to a point opposite Indian Island, 
the mussels occurred in patches along the sheer rocky shore and on the ledges 
in a strip from low-water mark to about four feet above it. Only at Clam Cove 
were any found on the beaches and here only a very few scattered among the 
sea-weed. 
At Wilson’s Beach no mussels were observed. At Macmaster Island a large 
bed was found. The mussels here were growing on the reefs and also on the 
sloping portions of the shore. On Adam Island only one small patch of mussels 
was found where observations were made, although the shore here was similar 
to the outer shore of Bliss Island. As explained previously the exact location of 
these points of observation could not be determined owing to a dense fog. 
In all places where mussels occurred the beds ended abruptly when low-water 
mark was reached. In the case of the beds on sloping shores the upper limit 
was in the region between one-third and one-half of the distance between low- 
and high-water marks. It was noticeable that no mussel beds were found on 
sloping gravelly shores, but always where the shore was muddy or sandy (the 
mussels soon render a sandy shore muddy) or on bare rocks. The writer is not 
able to offer any explanation as to why the mussels grew on some of the sheer 
rocky shores, e.g., Bliss Island and not on others, e.g., Adam Island. 
The variety pellucidus was found in the various beds described, but was not 
numerous. 
Size and Relative Numbers of Mussels in the Various Mussel Beds of the St. Andrews 
Region in 1917. 
Samples of the mussels were taken from the various beds and the living 
mussels taken from a known area were counted and the lengths of their shells 
measured to the nearest half-centimeter. The length of the mussel was con- 
sidered as the distance from the extreme anterior end of the shell to the extreme 
posterior end when the shell was placed with the edge from which the byssus 
protruded parallel with the scale. The samples of which the records are quoted 
were taken from typical portions of the mussel beds near low-water mark unless 
otherwise stated. 
The mussels in the various localities were all small. The largest ones 
obtained were only 6.5 cm. in length and only two were taken of this size. These 
were found in a sample taken from the rocky bottom beside Niger Reef, from an 
area of 102.5 sq. cm. Only 20 living specimens were obtained in the sample, 
which was taken from a small patch of mussels growing just at low-water mark 
somewhat isolated from the rest of the bed. In the main bed the mussels were 
of the usual small size (none obtained being over 4.5 cm. in length), but from the - 
above mentioned sample 17 out of the 20 mussels taken were 5 cm. or over in 
length. In general the largest mussels were obtained from the reefs and rocky 
20 
