31 



hotter.* At Messrs. Barr & Oo.'s cooling pond, Paisley, I have 

 found them at a temperature of 85° Fahr.; the species was 

 Cypridopsis vidua. I may mention, in passing, that the species 

 which have come under my own observation as having been 

 subject to high temperature — viz., Cypris Icevis, Cypris incongricens, 

 and Cypridopsis vidua — were all unusually light in colour. For 

 some time I kept a gathering of Ostracoda in a broad shallow 

 vessel placed near my window. In the cold mornings of March 

 not one of them was to be seen; but further on in the day, when 

 the sun was hotter, the different species of Cypris came from their 

 hiding places in the mud to swarm about actively up the sides of 

 the vessel, more particularly on the side next the light; and the 

 non-swimmers (Candoncu) came more to the surface of the mud. 

 This I have often repeated with the same result — hence the better 

 prospect of collecting "when the sun shines." Yet good gatherings 

 may occasionally be made during the colder seasons of the year, 

 and I have even had some excellent hauls in the month of January, 

 when I had to break the ice and w^ork underneath it. These 

 gatherings were not only fair in numbers and variety, but con- 

 tained species not found as a rule in the same tarns during the 

 months of summer. It is by no means of rare occurrence to find 

 a species abundant at one season and entirely absent in the same 

 place at another. On returning to search the same lake or pool 

 after an interval of two or three months at any period of the year, all 

 the same species will seldom if ever be met with, or grouped in the 

 same proportions. As one instance amongst many I may state 

 that a gathering was taken on May 21, 1878, in the old dam which 

 supplied the Go van Colliery. It was about 70 yards in circum- 

 ference and a foot or two deep ; the whole was covered with 

 green confervce, rather ropy but not slimy, and a little grass round 

 the sides. The number of Ostracoda obtained was twelve species. 

 This gathering presented a remarkable feature in the excessive 

 abundance of Cypris reptans, far exceeding anything I had ever 

 seen before of this species. Another gathering was taken from the 

 same dam, November 20, 1878. There were little or no confervce 

 this time — nothing except a little grass round the sides and some 

 thin growths out from the margins towards the middle. Cypris 

 reptans was now only represented by a few examples, which were 



* Brady, Monograph Rec. Brit. Ostrac, p. 368. 



