BIOLOGY OF THE SCOTTISH LOCHS 
281 
Navicula mqjoi^ Kiitz. 
Vanheurckia i-Jiomhoides (Ehr.). 
Surirella hiseriata (Breb.). 
*S'. rohusta^ Ehr. General. 
Synedra idna (Nitzsch.). 
Melosira gramdcda (Ehr.). 
Amphipleura pellucida^ Kutz. 
Rhizosolenki longiseta, Zach. Local. 
R. eriensis, H. L. Sm. Local. 
Cyclotella (several species). 
A brief analysis of the preceding lists will prepare us for a com- 
parative study with the rest of Europe. The species marked in the 
list as " general are almost universal in the lochs of the mainland, 
and usually in the islands also. Those marked " local " have well- 
marked limits in their distribution, though they may be very common, 
and may even be in every part of the country, but only in a small 
proportion of lochs. Those marked " very local are only known 
in a few lochs. Those having no such indication are insufficiently 
known, or at least the collections do not furnish sufficient information, 
and such must be sought elsewhere. 
Zooplankton. — The list contains 14 Crustacea, 12 Rotifera, and 
4 Protozoa. 15 species (9 Crustacea and 6 Rotifera) are generally 
distributed in the lochs ; 15 species are considered local. 
Half of the generally distributed Crustacea are found all the year 
round — Diaptomus gracilis^ Cyclops strenuus^ Daphnia liyalina, and 
Bosmina ohtuslvodrls. The others have a limited season — Ilolopedium, 
Polyphemus, Byihotreplies^ Leptodora^ Diaphanosoma. 
All the generally distributed Rotifera appear to persist through- 
out the year. For some of the species there is hardly enough evidence 
to prove this, but at all events they are found throughout summer, 
autumn, and early winter, and in early spring they are present 
{Asplanchna bearing viviparously) before the larger lakes begin to 
rise in temperature. 
Phytoplankton. — Apart from the Desmids and Diatoms, no 
analysis of the phytoplankton will be attempted, as Dr Bachmann 
discusses these in his paper. ^ 
I have indicated in the list 9 Desmids and 5 Diatoms which 
appear to be generally distributed. They are : Clostermm kutzingii^ 
Euastriim verrucosum^ Xanthid'mm antilopeimi, Arthrodesmus incus, 
^ See Bachmann, " Vergleicliende Studien iiber das Phytojolankton von Seen 
Schottlands und der Schweiz," Archiv f. Hydrobiologie u. Planktonkmide, Bd. iii. 
p. 1, 1907. To include the dozens of species recorded by Bachmann in their 
proper places would involve rewriting this article ; the reader is therefore 
referred to the work itself. 
