A HISTORY OF NOTTINGHAMSHIRE 



C. mega/ops (Sars) and C. quadrangula (O. F. Mtlller). 1 Similarly, Daphnia vetula (Baird) 

 includes the two species Simocephalus vetulus (O. F. Mdller) and S. exspinosus (Koch), the 

 former ' one of the commonest of the British Cladocera,' the latter ' a fairly common species 

 in the south and east of England, but not yet recorded from the north or from Scotland. ' In 

 these there is no spiny prolongation of the shell such as occurs in Daphnia, and the head is 

 obtuse with a beak but little projecting. In 1903 Dr. A. M. Norman, F.R.S., pointed out 

 that the generic name Simocephalus (SchOdler) was pre-occupied, and changed it to Simosa. 

 Some specimens sent me by Professor Carr, ' which when alive were pea-green in colour,' and 

 which ' were excessively abundant among the water weeds in the canal at Cossall, Notts,' 

 proved on examination to be Simosa vetula. The three remaining species Eurycercus lamellatus 

 (O. F. Mailer), Acroperus harpa (Baird), and Chydorus sphaericus (O. F. Mailer) belong to a 

 family which has been not unfrequently, but not properly, named Lynceidcs. Correctly, it 

 should be named Chydoridae from its premier genus Chydorus (Leach). Here both branches 

 of the second antennae are three-jointed, there are five or six pairs of feet equally spaced, and 

 the intestine forms almost a double convolution. By these characters its numerous genera are 

 distinguishable from those of the Daphniida:. The Eurycercus, though like our Cladocera in 

 general, small enough in itself, is quite a monster compared with the other two species. It is 

 also lethargic in its habits, in contrast to the little spherical Chydorus, which is ever on the 

 move. The Acroperus is distinguished from Chydorus by its harp-shaped shell, the strings of the 

 harp being represented by the obliquely longitudinal ribbing of the transparent carapace. 



Lastly, the Ostracoda demand a brief notice. Concerning these Mr. Edwin Smith says, 

 ' The species most common in the neighbourhood of Nottingham are Cypris vidua, C. minuta, 

 C. aurantia. If you search carefully the surface of gravel in your aquarium you may chance 

 to see a little oblong horny speck making its way by fitful jerks. This will probably turn out 

 to be a rather large member of the same family, named Candona reptans. It has a comical 

 habit of creeping in preference to swimming. I have found it about here in meadow drains, 

 and have successfully bred it in my aquarium from season to season.' s Mr. Pratt's list 

 contains ' Cypris bistriata Pond at Gamston and ditch near Beeston.' This group differs 

 from the Cladocera in many ways, but strikingly in external form, inasmuch as the bivalved 

 shell or carapace makes no pretence of showing a distinct head. The body within the valves 

 shows little or no segmentation. The appendages, including the two pairs of antennae and the 

 mouth-organs, are limited to seven pairs, and do not always reach that number. 



According to the latest available authorities the four species mentioned by Mr. E. Smith 

 should now respectively be called Pionocypris vidua (O. F. Mtlller), 4 Cyclocypris lavis (O. F. 

 Muller), 6 Cyprinotus incongruens (Ramdohr),' and Erpetocypris reptans (Baird). 7 Mr. Pratt's 

 Cypris bistriata is presumably C. bistrigata (Jurine), and, if so, may be identical with Ilyocypris 

 gibba (Ramdohr) 8 or with Ilyocypris bradyi (G. O. Sars). 9 All these species belong to the section 

 called Podocopa, in which the second antennae are simple, subpediform, geniculate, furnished 

 with terminal curved spines called ungues, and the first maxillae have a branchial appendage. 

 The family to which these species all alike belong is called Cyprididae. Therein only the last 

 two pairs of limbs are pediform, ' the preceding pair small and maxilliform in female, larger 

 and modified for grasping in male ; furnished with a branchial appendage,' the caudal append- 

 ages are ' long, narrow, linear, terminating in ungues,' or else ' minute, consisting of setiform 

 processes, which run out to a very fine extremity.' 10 From such names as Erpetocypris, the 

 creeping Cypris, and Ilyocypris, the Cypris of the mud, something may be judged as to the 

 sluggish habits which some of these creatures have contracted. They are all very common in 

 England, with one very remarkable limitation to this quality of abundance. It is not without 

 reason that Pionocypris vidua is specifically called ' the widow,' for Professor G. O. Sars in 

 1889, when defining the genus (then called Cypridopsis), gives as one of the characters, 

 ' propagation exclusively parthenogenetical.' u Nevertheless, so unnatural an exclusiveness may 

 perhaps be doubted, for in the neighbouring genus Cypris, at one time supposed to share this 

 singular singleness of sex, males of various species, such as C. incongruens, have now been 

 repeatedly found. Yet Brady and Norman say, ' As far as we know the curious fact remains 



1 Scourfield, in Journ. Quekelt Microscopical Club, ser. 2, viii, 436 (1903). 



* Ibid. p. 435. 8 The Midland Naturalist, i, 17. 



* Brady and Norman, Trans. Roy. DubRn Soc. ser. 2, v, 726 (1896). 6 Ibid. p. 718. 

 8 Sars, Crustacean Fauna of Central Asia, pt. iii, p. 28 (1903). 



7 Brady and Norman, Trans. Roy. Dublin Soc. ser. 2, iv, p. 84 (1889). 



8 Ibid. p. 107. Op. cit. v, 728. 

 1 Ibid. p. 624. 11 Ibid. p. 725. 





