MOLLUSCOIDA. 
41 
the west, and the extreme north and south, as shown in the 
valuable catalogues of Messrs. Alder, Couch, Hincks, and 
Norman. Many species will doubtless yet be found at St. 
Andrews—though at present they appear to be confined to the 
other areas, which have been more thoroughly investigated by 
observers specially skilled in this department. Bicellaria 
ciliata and Bugula pur pur otincta seem to be more common at 
St. Andrews than in Shetland, the latter form being especially 
abundant and fine, and apparently taking the place of the 
B. plumosa of the southern shores; Menipea ternata and 
Bugula Murrayana are likewise in considerable profusion and 
in fine condition; while the southern Flustra chartacea is 
wholly absent. The species of the Membraniporida?, perhaps, 
are more abundant in Shetland; andth zLepralice are decidedly 
more numerous there and in the extreme south. Amongst the 
more conspicuous forms we notice the entire absence of Lepralia 
Pallasiana , so common in the extreme west and south, and 
of the characteristic L. innominata and L. jigularis of the 
latter. The Celleporidse are abundant, but the species are 
few. Cellepora avicularis is exceptionally rich, according to 
Mr. Hincks; and the same high authority in this department 
states that the sole specimen of Eschara Shenei is fine. 
The Cyclostomatous forms are not numerous; but all the 
examples are abundant; and the same may be said of the 
Ctenostomata. The late Dr. John Reid mentions Vesicularia 
spinosa as growing near low-water mark; but I have not been 
successful in finding it. The Zetlandic Hornera and the rich 
tufts of Amathia lendigera , so plentiful in the south, are 
altogether absent. 
On the whole it would appear that the Hebridean, Zetlandic, 
and southern waters furnish a richer field for the Polyzoa than 
our eastern shores, not only as regards the number of species, 
but the condition and size of the specimens. I need only 
allude, for instance, to the luxuriance of the branching 
Celleporidse and Reteporse of the Hebrides and Shetland, and 
the extraordinary beauty and profusion of the Escharidse and 
Lepraliae, and indeed of the whole group, in the extreme south 
and in the Channel Islands, both between tide-marks and on 
the shell-banks around. 
G 
