292 Part ITI —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. i 
1835. Lynceus harpe, Baird, Trans. Berw. Nat. Club, vol. i. p. 100, pl. ii. 
fig. 17 
fos WKS 
1841. Lynceus leucocephalus, Koch, Deutsch. Crust., Myriap. u Arach., p. 36, 
plex 
1850. Acroperus harpe, Baird, Brit. Entom., p. 129, pl. xvi. fig. 5. 
1884. Acroperus leucocephalus, Herrick, loc. cit., p. 81, pl. E, fig. 5, pl. i. 
ree, 9), 
This species is generally distributed and moderately common. For full 
description, see Baird, loc. czt., p. 129. 
Alonopsis (G. O. Sars). 
Alonopsis elongata, G. O. Sars. ua 
1848. Lynceus macrurus, Lievin, Die Branch. der Dan. Geg., p. 41. pl. x. fig. 1. 
1862. Alonopsis elongata, G. O. Sars, Om. de i Omeg. af Christi. forekom. Clad. 
Andet Bidrag., p. 41. 
1867. Lynceus elongatus, Nor. and Brady, loc. cit., p. 376, pl. xviii. fig. 1, 
pl. 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 under the microscope.” It does 
not seem to be a rare species. 
Leydigia (Kurz). 
Leydigia quadrangularis (Leydig). Pl. ii. figs. 5, a-b. 
1860. Lynceus quadrangularis, Leydig, Naturges. der Daphn., p. 221, pl. viii. 
fig. 59. 
1863. Alona leydigt, Sheedler, Neue Beit. zur Naturges. der Clad., p. 27. 
2 §©Leydigia quadrangularis, Kurz, Dodekas Neuer Cladoceren. 
1884. Leydigia quadrangularis, Herrick, doc. cit., p. 88, pl. 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 acanthocercoides, Fischer, and reproduce Fischer’s 
figures of the species. These figures do not agree with Herrick’s figure of 
post-abdomen of Leydigia quadrangularis, whereasthe Lochgelly specimens 
agree perfectly with Herrick’s description and figure. I have followed 
Herrick in adopting Kurz’s name for this Lynceid. 
Lynceus, Miller. - 
Lynceus tenuicaudis(G. O. Sars). 
1862. Alona tenwicaudis, G. O. Sars, op. cit., Andet Bidrag., p. 37. 
1867. Lynceus tenwicaudis, Nor. and Brady, loc. cit., p. 376, pl. xix. fig. 3. 
1884. Alona tenwicaudis, Herrick, loc. cit., p. 95, pl. 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.” 
Soe 
