of the Fishery Board for Scotland. 273 



Candona Candida (Muller). Generally distributed, frequent. 

 ,, lactea, Baird. Generally distributed, frequent. 

 ,, kingsleii, Brady and Robertson. North shore, not common. 

 ,, pubescens (Koch). Frequent and generally distributed. 

 Ilyocypris gibba (Muller). North side frequent ; south side rare. 

 Cytheridea lacustris (G. 0. Sars). Frequent all over the bottom of the loch. 

 Limnicy there sancti-patrici, . Brady and Robertson. Generally distributed, 

 common. 

 ,, inopinata, Baird. Generally distributed, not common. 



Cladocera. 



Daphnella brachyura (Lievin). Generally distributed, not common. 

 Daphnia pulex (Muller). Generally distributed, frequent. 



,, longispina, Muller. Generally distributed, abundant. 

 Bosmina longirostris, Muller. Iu surface tow-nettings, rare. 

 Ilyocryptus sordidus (Lievin). South shore, frequent. 

 Eurycercus lamellatus (Muller). Generally distributed, not common. 

 Acroperus harpa, Baird. North and south shores, frequent. 

 Alonopsls elongata, G. 0. Sars. South shore, not common. 

 Alona quadrangularis, Miiller. Common, north and south shores. 

 Alonella exigua, Lilljeborg. Frequent, north and south shores. 



,, nana, Baird. South shore, scarce. 

 Pleuroxus trigonellus, Muller. Common in the loch. 



,, uncinatus, Baird. In the middle of the loch, scarce. 

 Chydorus sphcericus, Muller. Generally distributed, common. 

 Monospilus tenuirodris, Fischer. South shore, scarce. 

 Polyphemus pediculus (Linne). Middle of the loch, scarce. 

 Bythotrephes longimanus, Leydig. In the middle of the loch, frequent. 

 Leptodora hyalina, Lilljeborg. In the middle of the loch, frequent. 



INSECTA. 



The larvae of insects were abundant in the loch, especially the larvae of 

 the Iphemeridae. The Libellulidae and Phryganidae were also represented 

 in the larval stage more or less frequently. Some idea may be formed of 

 the myriads of these organisms present in the loch when it is stated that a 

 conspicuous ridge composed of cast-off skins of insect larvae which had 

 been washed ashore during the preceding stormy weather extended along 

 the margin of the loch for a considerable distance. The curious so-called 

 1 water-bears ' (Tardigrada), now included in the class Arachnida, were 

 common among the decaying vegetable matter at the bottom. Species of 

 Notonectidae or ' water-bugs,' and of aquatic Coleoptera were also more 

 or less common, though their distribution seemed to be more localised. 



VERMES. 



This division of invertebrates was represented by several species — para- 

 sitic and non-parasitic. Among the former were Schistocephalus solidus, 

 Crepl., obtained by my son from the body-cavity of a Stickleback (Gas- 

 tei'osteus aculeatus), and a species of tape-worm (Bothriocephalus latvs ?) 

 several of which were found in the alimentary canal of the trout, six speci- 

 mens being taken from one fish. The heads of the parasites were fixed at 

 the extreme end of the cceca or blind tubes of the stomach, and their bodies 

 were so elongated as to extend well down into the intestine. Usually 

 one parasite occupied a ccecum. Tubifex rivulorum was very common in 

 the loch. The following species of Annelidae were also obtained : — 



Clepsine 6 — oculata. 



Clepsine sp., a very small form. 



Nephelis octoculata (?N. reticulata, Malm.). 



