Turner — Ecological Notes — Cladocera and Copepoda. 163 



in that same pond, at another season Bosmina atlantaen- 

 sis was found. 



26. bosmina atlantaensis Turner. 



Bosmina atlantaensis, Turner, '94, p. 23; pi. VII., fig. 12, 13. 

 Bosmina atlantaensis, Herrick & Turner, '95, p. 209; p. 273. 



In the light of our present knowledge of the genus, the 

 original description of this species was too condensed; 

 hence I am giving a more complete description. 



The shell is smooth; length greater than the height; the body uni- 

 formly arched from the caudo-dorsal margin to the beak, vental 

 margin straight; caudal margin less than half the greatest 

 height, which is slightly caudad of the middle. The flagellum is about 

 midway between the eye and the beak, or slightly nearer the beak. In 

 a few cases, there was a faint trace of a pigment fleck at the base 

 of the flagellum. The spine is short and slightly curved caudad; an- 

 tennules nearly twice as long as the greatest height of the animal. 

 They are slender and slightly, but uniformly, curved from the beak 

 to their tip. The sensory seta is much nearer to the beak than to 

 the tip of the antennules. 



This species is abundant in two permanent, no-outlet 

 ponds, in which the water had a temperature of from 10° 

 to 16° C. 



Ever since reading Burckhardt 's Faunistische und sys- 

 tematische Studien ueber das Zooplankton der grosseron 

 Seen der Schweiz und ihrer Grenzgebiete, I have been in- 

 clined to regard this as a variety of Bosmina longirostris; 

 but, since there is still some uncertainty in my mind, I 

 have not felt it wise to change the name. 



27. Bosmina reversaspina n. sp. 



PI. XXXVIII. f. 1. 



The body is longer than wide and the greatest height is in front 

 of the middle; indistinctly marked with irregular striae, which run, 

 approximately, parallel to the dorsal surface; on the head these lines 

 converge towards the front. In specimens mounted in Canada balsam, 

 no markings are visible on the lower part of the body, nor on the 

 head. The dorsal margin is uniformly convex, protruding a little in 

 front of the eye; ventral margin is nearly straight. The flagellum 

 is near the eye; the beak is short; antennules long and slightly curved. 

 The spines are long and stout and curved towards the front (cephalad), 

 toothed on the posterior borders. (In no other Bosmina do we find 

 a spine of this type). The postabdomen is truncated, convex at its 



