236 
MARINE AND ESTUARINE DIATOMS. 
SCHIZONEMA. 
Schizonema. Frustules naviculoid (boat-like) arranged confusedly or in a 
single file, within a capillary, sub-membranaceous single tubed, more or 
less branched frond, of nearly equal diameter throughout. 
S. crucigerum W Sm. Passamaquoddy Bay. (Plate II, Fig. 21.) 
SCOLIOPLEURA. 
Scoliopleura. A single species of this genus (Sc. tumida) was observed by 
Dr. A. A. Mackay in collections from Passamaquoddy Bay, but is unknown 
to the writer. 
STAURONEIS. 
Stauroneis. Frustules free, oblong or lanceolate. Valves convex, striated, 
with a median line and terminal nodules. Central nodule dilated into a 
band (Stauros) free from striae. General appearance like that of navicula, 
but easily distinguished by the “stauros” or cross. 
S. phoenicenteron Ehr. Kennebecasis. (Plate II, Fig. 22.) 
S. obliqua Passamaquoddy. (Plate II, Fig. 23.) 
S. anceps Ehr. 
S. spicula. Kennebecasis. 
STRIATELLA 
Striatella. Frustules united to form short filaments, attached by a long 
stipe. Individuals longitudinally striated, lateraly lanceolate, with a 
median line. Imperfectly silicious. (Plate II, Fig. 24.) 
S. unipunctata Ag. Kennebecasis, Passamaquoddy. 
SURIRELLA. 
Surirella. Frustules simple, free, ovate or elliptical. Valves with a longi- 
tudinal central line and margins produced into wings (alae). Canaliculi 
distinct, usually parallel. 
S. splendida Kutz. Kennebecasis. (Plate II, Fig. 26.) 
S. ovata Kutz. Kennebecasis, Harding’s Pt. 
S. ovalis Breb. Kennebecasis. (Plate II. Fig. 25.) 
S. Mollerianum Grun. Kennebecasis. (Plate II, Fig. 27). 
S. biseriata W Sm. Kennebecasis. 
S. constricta. Kennebecasis, St. Martins. 
S. gemma. (Plate II, Fig. 28). Passamaquoddy. 
S. striatula. Salt marsh, St. Martins. 
Surirella sp? Kennebecasis. (Plate II, Fig. 29.) 
