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 CRUSTACEANS the second antennae, Mr. Hodgson in his Synopsis speaks of the dorsal or external branch as the posterior, the ventral or inner as the ante- rior, while Dr. Baird does just the reverse. Specimens of Cladocera are usually figured with the head uppermost. When the antennae are erected the ventral branch faces forward, when they are depressed the dorsal one occupies this position. It is therefore inconvenient to dis- tinguish them by terms which have no fixity of application. Professor Lilljeborg distinguishes B. longirostris as having the spines of the caudal ungues in the female divided into two series, while in the other species of the genus the series is single. In the family Macrotrichida? Warwickshire lays claim to Ilyocryptus sordidus, Lievin, and Drepanotbrix dentata, Euren. Already in 1881, Mr. H. E. Forrest, F.R.M.S., had recorded the former as obtained ' probably from a small pond in Sutton Park near Birmingham.' 1 Mr. Hodgson gives its distribution as ' common : Kingswood, Olton Canal, Sutton.' The generic name alludes to its habit of hiding in the mud, and the specific name enforces the moral that mudlarks will still be muddy. The terminal claws in this genus are very long and the intestine straight, subapically dilated, whereas in Drepanotbrix the terminal claws are small and the intestine forms a large loop. The name of the latter genus signifies sickle-haired or sabre-haired, and alludes to a rather minute character. In the second antennas the inner branch has on its first joint a long seta or hair, which is slightly curved like a sabre, and without any articulation in the middle such as is found in the seta of the second joint. In framing generic characters for the Cladocera a census has been taken of the hairs on the second antenna?. Hence unwonted attention has been drawn to parts that might otherwise be thought rather insignificant. The specific name dentata alludes to the dorsal tooth or stout spine on the subcircular carapace. Of the fourth family, often called Lynceidae but more correctly Chydoridae, there are ten species assigned to Warwickshire : Chydorus spbtzricus (O. F. M.), 'abundant, clear water'; C. g/o&osus, Baird, ' not uncommon ' ; Eurycercus lamellatus (O. F. M.), ' abundant in clear weedy pools and canals ' ; Acroperus harpa harpcz, Baird, ' generally distributed, clear water ' ; ' Lynceus quadrangularis, canal, Olton ' ; Graptoleberis testudinaria, Fischer, ' Olton Reservoir ' ; Alonella nana (Baird), ' common : Kingswood, Olton, Barnt Green ' ; Peracantha truncata (O. F. M.), 'canal, Olton; Alvechurch ' ; Pleuroxus trigonellus (O. F. M.), ' Alve- church ' ; P. uncinatus, Baird, ' canal, Olton ; Windley Pool, Sutton.' In regard to Lynceus quadrangularis, O. F. M., it needs to be explained that the genus Lynceus was established by O. F. M tiller, one of the chief pioneers in entomostracan science. But, as so often happens when new paths are opened up in zoology, this early genus was far too comprehensive for subsequent requirements. It had to be much restricted, and is now properly confined to the Phyllopoda. The Cladocera once included in it are distributed under various other generic 1 Midland Naturalist, iv. I. pi. I. 181