THE PLANKTON DIATOMS OF THE BAY OF FUNDY 19 



SESSIONAL PAPER No. 39b 



Fig. 15. A group resembling Th. Nordenskioldu, but having the cells con- 

 nected not by one but by many threads. It may be Coscinosira polychorda. 



Fig. 16. Thalassiosira. A series of biconcave discs, connected by a single 

 fine thread or filament. It may be Th. hyalina of Grun. 



Fig. 18. Asterionella. Forms of this beautiful genus are not very un- 

 common in the plankton of Passamaquoddy Bay and adjacent waters. In the 

 specimen represented six frustules were observed as grouped in a semi-circle by 

 the attachment of their bases, each frustule being cuneate or triangular with the 

 apex of each prolonged into a rigid spine. The species may be As. Japonica, Cleve, 

 which occurs in the North Sea, but the spines are more clearly differentiated than 

 in that species as figured by Gran. 



Plate III. Fig. 1-2. Chaetoceros horeale — Bail. 



I have not myself observed this species with certainty, but it is common in 

 the North Atlantic and is doubtless to be found in the waters of the Bay of Fundy. 

 It is mentioned by Dr. Ramsay Wright as seen by him at Canso, N.S. The figure 

 here given is taken from that of Dr. Gran in theNordisches Plankton. 



Fig. 3. A chain of auxospores probably of Chaetoceros decipiens. 



Fig. 4. This form, like many species of Thalassiosira, bears much resemblance 

 to a Melosira, but, unlike the forms referred to this genus, has the cells connected 

 not by a single thread but by several. In this respect it resembles the species 

 described and figured by Gran as Coscinosira polychorda. Only one specimen 

 was seen, gathered in early June from Deer Island. Without closer examination 

 of the cell-structure its identity could not be determined with certainty. 



Fig. 5. This species may be a variety of Thalassiosira gravida, Cleve. 



Fig. 6. A chain of frustules of Thalassiosira Nordenskioldii. 



Fig. 7. This is apparently a Thalassiosira, but has not been determined. 



Fig. 8. This would appear to be Th. gravida, Cleve, the slightly separated 

 quadrangular frustules bearing bristles at the slightly truncated angles. 



Fig. 9. This form has been figured and described under the name of Dicladia 

 capreolus, but is probably only an auxospore of some species of Chaetoceros. 



Fig. 10. Sydendrium diadema Gr. This form is occasionally, but rarely met 

 with. It belongs to the Chaetoceros family. 



Plate III. Fig 11. Actinoptychus undulatus — Kutz. 



This beautiful form is too well known to require description here. It is one 

 of the most common forms in the coastal waters of New Brunswick and Prince 

 Fidward Island, and is to be found in nearly all gatherings therefrom. 



39b— 2 



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