178 Proceedings of the Royal Physical Society. 



6. Daphnia longispina, 0. F. Miiller. 



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



12, figs. 8-10. 

 1850. Daphnia pulex, var. longispina) Baird, Brit. Entom., p. 91, 



pi. vii. figs. 3, 4. 



Habitat. — Duddingston Loch (?). A form very common in 

 Duddingston Loch appears to belong to this species. The 

 same form is also common in Loch Leven, and in several 

 other small lakes and ponds. D. longispina differs from the 

 last in the post-abdominal claw being without a pectinate 

 fringe of small hairs at the base. The shell is also usually 

 furnished with a moderately long and slender posterior spine. 

 There appear to be several varieties of D. longispina,. A variety 

 with a curious sloping head (var. nasuta, G. 0. Sars) was found 

 in Loch Doon in Ayrshire. Immature individuals are some- 

 times furnished with a " vertex tooth " (cf. var. hamata). 



7. Daphnia hyalina, Leydig, var. pellucida, P. E. Miiller. 



Habitat. — Duddingston Loch (G. S. Brady). This may turn 

 out to be only another form of D. longispina, 0. F. Miiller. 



8. Daphnia lacustris, G. 0. Sars. 



1862. Daphnia lacustris, G. 0. Sars, Om de i Omegnen af Christiania 



forekonrmen de Cladocerer, Forhandl. 

 Vidensk. Selsk. Christ. (1861), p. 19. 

 1899. ,, ,, T. Scott, Seventeenth F. B. Rept., pt. iii. 



pp. 192-194, pi. vii. figs. 29-33, 34 and 34a. 



Habitat. — Loch Leven (G. S. Brady). Probably frequent. 

 Hurley Cove, Penicuik, 31st December 1900, common (Dr and 

 Miss Sprague). This species possesses when young, and some- 

 times also in the adult stage, a " vertex tooth," which may be 

 single or double. D. lacustris is, by some writers, considered 

 to be a variety of the last species (D. hyalina), to which it 

 bears a close resemblance. 



9. Daphnia galeata, G. 0. Sars. 



1863. Daphnia galeata, G. 0. Sars, Om en i Somm. 1862 fortagen 



Zool. Reise i Christ, og Throndh. stifter, p. 21. 

 1899. Daphnia galeata, T. Scott, Seventeenth F. B. Rept., pt. iii. 

 p. 193, pi. vii. figs. 22, 53, see also fig. 16. 



Habitat. — Loch Katrine, Loch Achray, and Loch Vennachar. 



