[bailey] the diatoms OF NEW BRUNSWICK 71 



Odontidium — Four species occur in New Brunswick waters, but excepting 0. 

 mutabileS. B.D., and 0. hyemale found in the Kennebecasis, they are confined 

 to north shore points, and are of infrequent occurrence. 



Plagiotropis. — This genus is represented by the single species PI. vitrea-Grun, 

 which was found at St. Martin on the southern coast and at several points on 

 the Bay Chaleur. It is rather common in the harbors of Charlottetown, Sum- 

 merside and Souris, P.E.I. 



Plagiogramma. — The species Flag. Gregorianum has been found at Malpeque and 

 Charlottetown, P.E.I, but has not yet been observed in New Brunswick waters. 



Pleurosigma. — This genus, also known as Gyrosigma, has many species, of which 

 some are found in most gatherings. PI. attenuatum-W.S., and PI. spencerii- 

 W.S., are fresh water forms, both being found in Chamcook Lake and in infusor- 

 ial deposits, but also in Passamaquoddy Bay. P. Baltium is a common and 

 conspicuous form, occurring in the St. Croix River and Passamaquoddy Bay 

 and again at most north shore points. It abounds in the waters about Prince 

 Edward Island. PI. fasciola-W.S., probably comes next both in range and in 

 abundance, being found at the same points as P. Balticum, but only in salt or 

 brackish waters. The other species listed are less common, and mostly confined 

 to the salt waters of Passamaquoddy Bay. Five species, including some of 

 the above, are found in the brackish waters of the lower St. John, and nine 

 about the shores of Prince Edward Island. 



PoDOSPHENiA. — In the absence of stipes it is not easy to distinguish the species of 

 this genus from those of Rhipidophora, but it is believed that both P. Jurghensii 

 and P. Lyngboei are represented among the New Brunswick Diatoms, both 

 occurring in salt waters at Campbelton. 



Pyxidicula. — One species only, vizt., Pyx. compressa-Bail., has so far been observed. 

 It was found at Matthew's Cove on the Kennebecasis in slightly brackish water, 

 but is rare. Also in salt water at Campbelton, and the harbors of Prince Edward 

 Island. 



Raphoneis. — This genus, also kno-wn as Doryphora, has, in the region here considered, 

 two species, viz., R. Bœckii and R. amphiceros-Kutz. The former is the 

 more common and is of frequent occurrence on the North Shore. Though 

 naturally marine, it is found abundantly in the Kennebecasis even at consider- 

 able distances from the sea. R. amphiceros, though more rare, has the same 

 distribution. 



Rhabdonema. — The species of this genus, which are here three in number, are 

 confined to salt water. Rh. arcuatum-K., is found in nearly all marine gather- 

 ings, often in filaments. Rh. Adriaticum is much less common and so far 

 known only from the North Shore. Rh. minutum was observed in St. John 

 Harbor and Malpeque, P.E.I. 



Rhipidophora. — Several specimens, believed to be of this genus, have been obtained 

 in the waters about Passamaquoddy Bay, but the species was undetermined — 

 As stated in connection with Podosphenia they are not easily distinguished from 

 forms of that genus. 



Rhizosolenia. — This is peculiarly a plankton genus and is represented by two 

 species, Rh. styliformis and Rh. setigera. The former occurs abundantly, along 

 with other plankton forms, in the waters about the lower part of the Bay of 

 Fundy, also at Bathurst and around the shores of Prince Edward Island. Rh. 

 styliformis-Br . , was found at Newcastle. 



Rhoicosphenia. — Rh. curvata-Grun., occurs in the Kennebecasis; also at Chatham 

 and several northern points, as well as Charlottetown, P.E.I. 



