Notes on Gladocera. 91 



tween the valves and bent inward toward the median line, so that 

 the ends of the two hooks are almost in contact when at rest. 

 The ends are covered with fine teeth. The post- abdomen has the 

 same general shape as that of the female. The hairs on it are 

 finer, hardly perceptible. There are no terminal claws, and the 

 post-abdomen is prolonged into an elevation about 0.05 mm. 

 long, on whose summit the vas deferens opens. 



Madison, Wis., 1877. Kot rare in shallow and weedy water. 



Sub-family 3. Bosmininse. 



GENUS 1. 



BOSMINA. Baird, 1850. 



SPECIES 1. 



BosMiNA LoiSTGiROSTEis. 0. F. Miiller. 



Lynceus longirosteis, O. F. Miiller. Entomostraca, p. 76, Tab. X, flg3. 7-8. 

 BosMiNA " Sars, I. c, p. 153. 



" " Schodler. Cladoceren des frischen Haflfs. p. 45, figs. 



16-17. 

 " " P. E. Miiller. 1. c, p. 146, Tab. Ill, figs. 8-9. 



" " Kurz. 1. c, p. 29. 



Length, circ. 0.39 mm. 



These specimens agree with Bosmina longirostris in all respects 

 except size, which is considerably greater in our form. 



Cambridge and Southampton, Mass.; Madison, Wis. Eather 

 rare. 



SPECIES 2. 



Bosmina CoRisruTA. Jurine. 

 Plate 11. Fig. 10. 



MoNOCULUS COKNUTUS, Jurine. 1. c, p. 142, Tab. 14, figs. 8-10. 

 EiTNiCA LONGIROSTRIS, Kocli. 1. c, H. 35, Tab. XXIII. 

 Bosmina cornuta, Sars. 1, c, p. 280. 



" " Schodler. Clad. fr. Haffs. p. 49, Tab. Ill, figs. 18-22. 



P. E. Miiller, 1. c, p. 147. 



Specimens belonging to this species were found at Easthamp- 

 ton, Mass., Aug., 1878. Length, 0.3 mm. 



