CRUSTACEANS pulchella. Leach, has been obtained by Dr. Sorby in the River Orwell. For a long time the genus Jassa of Leach was confounded with his Podocerus, established at the same time, but really belong- ing to a different family.* Lastly, for the family Corophiidae a record is supplied by the Rev. E. N, Bloomfield, who, writing in August 1 902, says, 'in a very interesting letter from Dr. Harmer, F.R.S., of Cambridge, among various creatures met with by him in the salt water ditches near Aldborough, he mentions the very remarkable amphipod Corophium grossipes. This species should rather be called C. volutator (Pallas). All round our coasts it forms its tubular galleries in the mud of tidal swamps. From C. crassicorne (Bruzelius), which has been taken in almost fresh water in Norfolk, C. volutator is separated by a rather uncommon feature of distinction, the latter species having the fourth, fifth, and sixth segments of the pleon normally articulated, while in the former they are coalesced into a single piece. The Entomostraca form three principal groups, Branchiopoda, Ostracoda, Copepoda, each with various subdivisions. In the first only the Cladocera now need our attention. Of these the following examples may be specified. From a small pond near Oulton on 1 4 May 1 907, a specimen of Daphnia pulex (De Geer) was taken, corresponding with the figure given by Lilljeborg of a young male taken at Upsala, not in the spring but early in September, and described as Mas junior autumnalis?^ To the same family Daphniidae belongs Simosa vetula (O. F. MuUer), of which specimens were obtained from a ditch near Oulton, 13 May 1907. These agree perfectly with Lilljeborg's account and figures of the femina adulta vernalis.^ The veteran Swedish anthor states that the female of this species, like Daphnia pulex, is largest in the spring, being about 3 mm. long, and having then the largest number of eggs in the brood cavity, its shape broad oval, strongly narrowed in front. In this genus it may be noted that the four-jointed branch of the second or swimming antennae has one of the apical setae shorter than the other two, minutely uncinate and thereby prehensile. On the hind body S. vetula has two processes, the anterior standing nearly upright, the other smaller, bent forward. Behind the caudal setae the upper margin of the tail-piece runs to an angle, between which and the ungues a very sinuous border carries from nine to ten spines. The ungues are distinguished from those of other species in the genus by the microscopic fineness of their spinules. The name vetula, as given by Mailer, may originally have included more than one species. As defined by Schoedler in 1858 it is now generally accepted for the form here described. A male specimen was obtained, as well as several of the other sex. In the family Chydoridae, at the same time and place with S. vetula one example of Eurycercus lamellatus (O.F.M.) was taken. This family differs from the Daphniidae by having both branches of the swimming antennae instead of only one of them three-jointed, and by having the intestine with instead of without a loop. Eurycercus agrees with the Daphniidae in that the intestine has in front two caecal appendages, which are not present in other members of the Chydoridae. E. lamellatus has the first antennae thick, with the sensory seta placed near the middle of their single joint. Lilljeborg gives the length of the female as ranging between 3 and 4 mm., the size somewhat larger in spring and summer than in autumn, less in brackish water than in fresh." Under the microscope the tail-piece is a pleasing object with its fringe of 1 00-120 spinules. These gradually increase in size as they pass from the caudal setae to an angle which is separated from the ungues by a deep sinus. Near the ungues the sinus also carries spines and spinules. Chydorus sphaericus (O.F.M.), a tiny dwarf in comparison with the two preceding species, is abundant at Lowestoft, as it appears to be in suitable waters all over the globe. The sexual differences in this species are well marked, the rostrum of the female being acute, that of the male obtuse, and the tail of the male being strongly emarginate at the anal fissure, instead of shallowly as in the female. For the Ostracoda of Suffolk, the paper by G. S. Brady and David Robertson, published in the Annals and Magazine of Natural History for July 1870," is the leading authority. The authors say : 'The Entomostraca of the tidal rivers of Norfolk, Suffolk, and the Cambridge fen-district con- stitute so remarkable a group that it seems best to speak of them separately, and in so doing we shall call the area to which we refer the East Anglian District, understanding by that term the whole tract drained by the rivers Nene, Cam, Bure, Yare, and Waveney. The drainage tract of the adjoining rivers on the south. Aid, Deben, Stour, &c., is separated by rising ground, and appears to be zoologically distinct.' Speaking of the Broads of Norfolk and Suffolk in general, they say that they may be considered as expansions of the various tidal rivers, though situated at such distances from the sea as to be but slightly influenced by tidal ebb and flow. As to those with which we are here more especially concerned, they write : ' Lake Lothing is a tidal expanse separated from Oulton Broad, at i^s western extremity, by an embankment, through which canal boats pass by means of a lock. In this way some slight communication exists between the waters of the two basins, but the true outlet of Oulton Broad is by the River Waveney, which from this point takes a circuitous " Das Tierreich, Amph. Gamm. (1906), 21, pp. 654, 739. " Cladocera Sueciae, pi. xii, fig. 12. " Ibid. 167, pi. xxiv, figs. 8-18. " Ibid. 386. " Op. cit. 1-33, pis. iv-x. 159
