Rotatoria E 9 



The posterior segment of the body is roughly trapezoidal in oultline and 

 cuspidate at the posterior angles; the margin is convex in the median portion 

 and has a slight concavity at the angles. There is a well marked constriction 

 at the junction of the ventral plate and the posterior segment. The coxal 

 plates are semi-ovate. 



The first foot joint is well marked and widest posteriorly; the second foot 

 joint is nearly square. The toes are short, cylindric for one half their length 

 and end in acute, conical points. 



Total length 126 /z, length of lorica lOS/*; length of dorsal plate 93^; width 

 13 //; width of ventral plate 96 /*; width of anterior points 58 ju; length of toes 

 27 /JL. 



Lecane jessupi had some resemblance to L. brachydactyla (Stenroos), which 

 is shown on plate 3, figs. 5, 6, for comparison. The differences are fairly evident: 

 L. brachydactyla has anterior spines and a straight, somewhat flexible dorsal 

 margin, a double-curved ventral margin and the posterior segment is very 

 simple in outline. L. jessupi was collected by Jessup in lakes on Old Crow 

 river flats, 40 miles north of New Rampart House, on July 3, 1911; it was 

 not abundant. 



Lecane luna (Miiller). 



Cathypna luna HUDSON and GOSSE, Rotifera, 1886, vol. 2, p. 94, pi. 24, fig. 4. 



Apparently not common in the Arctic; it was collected by Jessup from two 

 Fakes on Old Crow river flats, 55 miles north of New Rampart House, on July 

 10, 1911, and ponds on Old Crow river flats, 60 miles north of New Rampart 

 House, on July 11, 1911. 



Lecane ungulata (Gosse). 



Cathypna minnesotensis MURRAY, Journ. Royal Micr. Soc., 1913, p. 345, 

 pi. 13, fig. 18. 



A few specimens in a collection made by Jessup from two lakes on Old Crow 

 river flats, 55 miles north of New Rampart House, on July 10, 1911. 



Lecane clara (Bryce). 



Distyla clara BRYCE, Science Gossip, vol. 28, 1892, p. 271, text fig. 



Collected by Jessup from lakes on Old Crow river flats, 40 miles north of 

 New Rampart House, on July 3, 1911, and in a slough of Old Crow river, near 

 New Rampart House, on August 7, 1912. Only a few specimens were found 

 in each collection. 



Lecane depressa (Bryce). 



Distyla depressa BRYCE, Science Gossip, vol. 28, 1892, p. 271, text fig. 



Common in a collection made by Johansen among algae growing on stones 

 in the river bed at Bernard harbour, on August 16, 1915. In Jessup's col- 

 lections from lakes on Old Crow river flats, 35 miles north of New Rampart 

 House, on June 23, 1911; muskeg lake, 28 miles north of New Rampart House, 

 on June 25, 1911; lakes on Old Crow river flats, 40 miles north of New Rampart 

 House, on July 3, 1911; lakes on Old Crow river flats, 60 miles north of New 

 Rampart House, on July 11, 1911; small muddy pool, 25 miles north of New 

 Rampart House, on July 17, 1911. 



Lecane flexilis (Gosse). 



Lecane flexilis HARRING, Proc. U. S. Nat. Mus., vol. 47, 1914, p. 538, pi. 19, 

 figs. 1-3. 



