NOTES ON FRESH AND BRACKISH-WATER ENTOMOSTRACA 23 
to the Cladocera, while the remainder was about equally 
divided between the two groups mentioned above. 
A small portion of the north shore bordering the Water- 
side Road had been examined during an earlier visit, viz. on 
6th July, when about twenty species of Entomostraca were 
obtained, five of which were not observed in August. On 
6th July the tide was flowing, and while watching the 
gradual and steady advance of the water upon the land, I 
noticed myriads of Schizopods crowding up with the advanc- 
ing water, all of which appeared to be eagerly seeking for 
and catching the minute organisms that were being stirred 
into activity by the incoming tide. A single dip of the 
hand net was sufficient to capture a considerable number 
of these busy crustaceans, and when examined at close 
quarters they were found to consist entirely of Neomysis 
vulgaris (J. V. Thompson). Lower down the river, where 
the conditions become more estuarine, there are forests of 
tall reeds growing along the river side; here in pools in the 
mud the curious amphipod Corophium grossipes was obtained. 
The total number of Entomostracan species captured 
during my three visits to the Ythan is sixty-five, seventeen 
of them belonging to the Cladocera, twenty-six to the 
Ostracoda, and twenty-two to the Copepoda. Included 
amongst these were seven species of the Ostracoda and six 
of Copepoda which are more or less decidedly brackish-water 
forms. 
The following are the names of the species captured on 
these three occasions, their abundance or rarity being 
indicated by the following abbreviations — c. = common, 
n.c.=not very common, r.=rare, and v.r.=very rare; a 
blank, that it was not obtained at that particular visit, and an 
* is placed opposite the names of the brackish-water species. 
CLADOCERA. | 
1st Visit, 2nd Visit, 3rd Visit, 
July 6. July 13. Aug. 24. 
Certodaphnia quadrangula, Miiller Ave. 
Scapholeberis mucronatus, Miiller . IC 
Simocephalus vetulus, Miiller C; 
Daphnia longispina, Leydig : Ge 
Losmina longtrostris (Miller) 
Llyocryptus sordidus (Lieven) Marie: €. 
