104 * DEPARTMENT OF THE NAVAL SERVICE 
7 GEORGE V, A. 1917 
Of its species the most common is B. aurita, found on almost all gatherings, and at 
almost every season. It occurs in January at the Biological Station; at St. Andrews, 
again in February; in March and April at various stations on the St. Croix river and 
Passamaquoddy bay, as also in June and July. It is common in the waters of St. 
John harbour in August, and probably occurs, though not yet recorded, in the later 
months. No examples were noted in the “ Prince” series. The much larger species 
B. Mobilensis (—B. Baileyi) was found at Chance harbour, Bald Head, Campo Bello, 
St. John harbour, Seely’s Cove, and Lepreau, at different dates in January (the water 
temperature being 33° F.), and on February 14 at the Reversing Falls, St. John. It 
was not observed during the summer months about Passamaquoddy bay, but at Tyne- 
mouth creek, in St. John county, in August, it was so abundant as to make up the bulk 
of the plankton, and on September 27, it was found but rarely in the Bay of Fundy 
between St. John and Digby Gut. It would appear to be more common in deep water, 
and is one of the species quoted as being characteristic of the European plankton. 
B. pulchella was found in St. Andrews harbour, February 19, and again March 17, and 
April 19, but it 1s very rare. 
Chaetoceras.—This is the most typical, as it is also the most common and wide- 
spread of all the genera which distinguish the Phyto-plankton. Of the several species 
represented, by far the most common, both as to numbers, time, and place, is 
C. decipiens usually easily recognized by the narrow slit-like form of the inter-cellular 
spaces. It was abundant on January 1, at the Biological Station, and throughout the 
month at other points about Passamaquoddy bay, accompanied, though much less 
abundantly, by the C. sociale. Both of these species, but with the same difference in 
relative numbers, were found through February in St. Andrews harbour, and again in 
March, extending up the St. Croix river to and above Doucett’s island. Both species 
were similarly found all through April and May but became less common in June, and 
still less, in the latter months, though both were found at Eastport July 29, and Campo- 
belle August 1. No specimens were found in the August plankton of St. Martin’s or 
St. John, though found during this month in collections from L’Etang and Deadman’s 
harbour. In the “ Prince” series the only records of this genus are Chaetoceras 
decipiens at the eastern entrance of St. Andrew’s harbour October 16, and the same 
species at Grand Manan, but rarely, on October 3 and 27. 
Coscinodiscus.—This genus is almost invariably present in the marine plankton, 
and sometimes to the exclusion of almost everything else. The most common species 
is C. asteromphalus, Ehr., easily distinguished by the conspicuous central rosette of 
cells; and C. concinnus, remarkable for its large size, fine radial sculpture, and short 
marginal striz. Both species were found at Campo Bello and Seely’s Cove in 
January; but not commonly. Both again were obtained in St. Andrews harbour, 
February 19 and March 18, and were abundant at La Tete, March 28. They were 
common in April in St. Andrews, as also in succeeding months at many different 
stations both in Passamaquoddy bay and the bay of Fundy. In almost all instances 
ihey were accompanied by the much smaller species (. eccentricus and less frequently 
by C. radiatus. 
Ditylum.—This genus, though frequently, and sometimes abundantly represented 
in the plankton of the bay of Fundy and Passamaquoddy bay, is one as to whose 
relationships much doubt still exists. First named and described by the flate 
Professor J. W. Bailey of West Point, N.Y., it was subsequently referred, by 
West and others, to Triceratiwm, while this latter genus was itself later referred to 
Biddulphia. xcept, however, in the outline of the valves, varying, as in Triceratium 
from triangular to quedrangular and pentagonal, it bears, as remarked by Mann in 
his report on the Diatoms of the Albatross Expedition, not the remotest resemblance 
to the genns last named. 
