168 



stream. The specimens show a considerable range not only in 

 size but in the ornamentation dependent on the number of septal 

 lines, sutural punctations, and the variable development of the 

 retral processes. A few examples show very deeply sunken sep- 

 tal lines, giving a crenate feature to the peripheral outline. 



P. macella, Fichtel and Moll. A much depressed variety of 

 P. crispa, and is the shallow-water and starved condition of the 

 latter species. It is limited to the littoral of the warmer seas. 

 Not so common as the last described species, but is moderately 

 plentiful in association with P. striato-punctata on muddy flats of 

 North Arm. 



The above list contains fifty-one species, belonging to fifteen 

 genera, of which six species at least may be regarded as doubtful 

 occurrences in the living condition. The fauna, as a whole, is 

 characteristic of shallow water and a temperate climate. Thirty- 

 five of the species identified (which is equal to two-thirds of the 

 whole) are living in British waters, whilst the remaining sixteen 

 species, with one or two exceptions, are known as Australian or 

 .sub-tropical species. The objects of greatest interest in the fauna 

 under consideration are the foraminifera with arenaceous tests, of 

 which there are nine species present. I can find no record of the 

 occurrence of M. fusca, Brady, beyond the limits of the estuarine 

 waters of Britain. The rare Trochammina injiata, also a British 

 ■estuarine species, occurs in considerable numbers high up the 

 stream, and exhibits precisely the same peculiarities of shell- 

 structure as are found in its congeners in the Northern Hemi- 

 sphere. The still rarer species, Haplophragmium cassis, the 

 geographical distribution of which, as previously known, was 

 limited to a few points on the borders of the Arctic Circle, is not 

 uncommon in some positions in the river. Reophax nodulosa is 

 also a characteristic cold water species, living at abyssal depths, 

 where the temperature is low, and reaches its greateat develop- 

 ments in size in Arctic and Antarctic waters. Reophax findens 

 is a very rare form, limited to two localities in previous re- 

 searches, one of which is the Gulf of St. Lawrence, where it was 

 first discovered in association with //. cassis. The finding of 

 these very rare forms in company in the Southern Hemisphere, 

 agreeing with a like association in the Northern Hemisphere, is 

 a^" coincidence as remarkable as it was unexpected. The presence 

 of several Arctic and sub- Arctic species in our local waters sup- 

 plies matter for speculation as to the possible migration of these 

 and other forms to lower latitudes during a period of greater 

 cold, and, in this way, reaching the southern shores of Australia, 

 where they still maintain a lingering existence. 



