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Part III. — Ninth Annual Report 
A large and easily identified species. The post-abdomen is " a broad 
flattened plate with a very closely serrated margin." 
Acroperus, Baird. 
Acroperus harpa, Baird. 
1835. Lynceus harpce, Baird, Trans. Berw. Nat. Club, vol. i. p. 100, pi. ii. 
fig. 17. 
1841. Lynceus leucocephalus, Koch, Deutsch. Crust., Myriap. u Arach., p. 36, 
pi. X. 
1850. Acroper^us har2)ce, Baird, Brit. Eutoin,, p. 129, pi. xvi. fig. 5. 
1884. Acrope7'us leucocephalus, Herrick, loc. cit., p. 81, pi. E, fig. 5, pi. i. 
fig. 9. 
This species is generally distributed and moderately common. For full 
description, see Baird, loc. cit., p. 129. 
Alonopsis (G. O. Sars). 
Alonopsis elongata, G. 0. Sars. 
1848. Lynceus macrurus, Lievin, Die Branch. derDan. Geg., p. 41. pi. x. fig. 1. 
1862. Alonopsis elongata, G. 0. Sars, Om, de i Omeg. af Christi. forekom. Clad. 
Audet Bidrag., p. 41. 
1867. Lynceus elongatus, Nor. and Brady, loc. cit., p. 376, pi. xviii. fig. 1, 
pi. xxi. fig. 2. 
1884. Alonopsis elongata, Herrick, loc. cit., p. 85. 
This species is larger than Lynceus quadrangularis, for which it has 
probably sometimes been mistaken. It is easily distinguished " by the 
presence of the three spines, which spring from the terminal claws of the 
abdomen, and which are very conspicuous ucder the microscope." It does 
not seem to be a rare species. 
Leydigia (Kurz). 
Leydigia qimdrangidaris (Leydig). PI. ii. figs. 5, a-h. 
1860. Lynceus quadrangulai'is, Leydig, Naturges. der Daphn., p. 221, pi. viii. 
fig. 59. 
1863. Alona leydigii, Shoedler, Neue Beit, zur Naturges. der Clad., p. 27. 
? Leydigia qaadrangularis, Kurz, Dodekas Neuer Cladoceren. 
1884. Leydigia quadrangularis, Herrick, loc. cit., p. 88, pi. H, fig. 4. 
This species is easily identified by the remarkably broad and almost 
semicircular post -abdomen. Norman and Brady include Alona leydigii, 
Schoedler, with Lynceus acantliocercoides, Fischer, and reproduce Fischer's 
figures of the species. These figures do not agree with Herrick's figure of 
post-abdomen of Leydigia qaadrangularis, whereas the Lochgelly specimens 
agree perfectly with Herrick's description and figure. I have followed 
Herrick in adopting Kurz's name for this Lynceid. 
Lynceus., Miiller. 
Lynceus te7iuicaudis{(j. 0. Sars). 
1862. Alona tenuicaudis, G. 0. Sars, op. cit., Andet Bidrag., p. 37. 
1867. Lynceus tcmdcaiidis, Nor. and Brady, loc. cit, p. 376, pi. xix. fig. 3. 
1884. Alona tenuicaudis, Herrick, loc. cit., p. 95, pi. i. fig. 2. 
This species is easily recognised by the form and armature of the post- 
abdomen, which is long, with the sides nearly parallel, " incised below, 
lower angle armed with about six strong teeth, the remainder of the series 
small." 
