228 ON THE BKITISH SfECIES OF ENTOMOSTEACA 



my friend the Eev. Canon IS'orman at "Wallington, Northumber- 

 land, and in a pond near the East Gate of Lambton Park, county 

 Durham. The Wallington specimens were the more numerous, 

 but the males were very scarce, and no ovigerous females have 

 been seen. The male antennule, as shown in fig. 13, is probably 

 imperfect. Herrick describes it as having in D. minnehaha a 

 long flagellum in addition to the shorter sensory organs. 



M. Jules Richard looks upon D. minnehaha, Herrick, as being 

 merely a variety of D. piilex, but his figure scarcely agrees either 

 with that of Herrick or with the specimens here described. The 

 fact that no ovigerous females have been seen suggests the idea 

 that they may belong to an immature form of some other species. 

 But the only British species which comes near them in general 

 character is D. pulex, and no one has ever noticed in its young 

 the pecaliarities of D. minnehaha or B. hamata. For the present, 

 therefore, I regard this as a distinct specific form, its salient 

 characters being the position of the eye near the middle of the 

 head, the large and obliquely projected posterior spine which, 

 however, in the adult would probably become median in position, 

 the 4-5 dentate dorsal angle of the male and immature female, 

 the small antennule and smooth, straight abdominal process of 

 the male. 



Daphnia minnehaha of Herrick makes a very near approach 

 to this form but differs in some details — particularly as to the 

 head and antennules of the male. 



Daphnia longispina, 0. F. Midler, (PI. YIII., figs. 11-19). 

 1785. Daphnia longispina, 0. F. Miiller, Entomostraca, p. 88, 



pi. XII., figs. 8-10. 

 1850. ,, pulex, var. Baird, Nat. Hist. Brit. Entoui., 



pl. YII., fig. 3. 

 1 860. , , longispina, Leydig, Naturgeschichte der Daph- 



uiden, p. 141, pl. II., figs. 13-20. 

 1871. ,, ,, Fric, Die Krustenthiere Bohmeus, 



p. 233, fig. 36. 



Female. — The outline as seen from the side (fig. 14) is rather 



elongated and ovate, the length, exclusive of the spine, being 



equal to nearly twice the height. The head is rounded, though 



