388 
Proceedings of the Iloyal Society 
late Dr Johnston of Berwick, and to the splendid monograph of 
Messrs Alder and Hancock. 
Inhabitants for the most part of the laminarian and littoral 
zones, the rocks and rock-pools, by minute and continued search, 
produced the greater number of those met with at St Andrews, the 
few others being procured from fishing-boats and debris of storms. 
Almost all require to be sought for with care, and generally 
escape superficial notice altogether. Most have been kept for a 
longer or shorter period in confinement, and some are living 
even now, though with greatly diminished bodies, and less bril- 
liant tints, the results of insufficient food and other unfavourable 
circumstances. 
Their favourite haunts are under stones in pools, and the more 
undisturbed these look, the better chance is there of securing fine 
specimens. The upturned surface of the stone, however, should 
be immersed an inch or two under the clear water, so as to float out 
the branches of the zoophytes and the branchise of the Eolids. The 
fondness of the smaller forms for surfaces covered with Sertularidee 
is also seen in the case of storms, where the richest fields are the 
broad blades of the LaminaricC that are covered with Laomedea geni- 
culata and gelatinosa. 
The species met with at St Andrews will be given in the order 
in which they occur in the ‘‘Monograph” above-mentioned, with 
such remarks appended to each as may seem necessary or new. 
The most plentiful JSTudibranch here, as elsewhere, is Doris tu- 
bercidata, wdiich occurs in all sorts of places amongst the rocks at 
low water. In storms, many are found on the west sands in the 
intricate hollows of large masses of Halichondria panicea^ a situa- 
tion affording them both food and shelter. Some, found under 
large stones in pools, were unusually flattened and rounded, like 
gigantic Lamellariee : such are not gaily tinted. Most of the 
specimens, especially those of large size, had some of the parasites 
described by Alder and Hancock under the name of Ergasilus, 
which sported over their branchise and other organs with wonderful 
agility. Messrs Alder and Hancock state that they are colourless, 
but in most cases these had a pure white cross on the back, and 
some were pinkish. The largest Doris measured fully 4f inches. 
Their food, as usual, is Halichondria panicea. 
