NUDIBRAN CHI ATA. 
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among oysters brought to Belfast market from the neighbouring coast of 
Down or Antrim, and after noting their general appearance, colour, &c., 
set them apart as species unknown at least to the British Fauna. Mr. 
Alder having some time ago expressed a wish to see my collection of 
Nudibranchiate Mollusca, it was placed in his hands, and, on this species 
coming under examination, it was considered by him and Mr. Hancock 
to be new, and a description of it drawn up for their own use was kindly 
communicated to me. This is as follows ; — within parentheses are my 
notes on the colour of the living Boris. 
Doris Ulidiana. — “ Length, from spirits, £ inch, breadth ^ inch ; 
ovate-oblong, rather straight at the sides, depressed [of a uniform pale 
yellow, the intestines appearing through the skin of a dark colour]. 
Cloak not extending much beyond the foot, rough with spicula, and 
covered with large, unequal, obtuse tubercles, the spicula collected in 
bundles in the tubercles and radiating at their base. Tentacula [long and 
whitish] lamellated, without sheaths ; the edges of the apertures plain. 
Branchiae consisting of eleven [beautifully white] pinnated plumes, set in 
a semicircle round the anus. Foot rather broad. Veil above the mouth 
semicircular.” 
On being put in diluted spirits of wine, the tentacula were entirely 
withdrawn, and the branchial processes lost their beauty by discoloration, 
which changed them to the same hue as that of the body. 
On comparing these specimens at the time they were procured with the 
most nearly allied species in my possession, the Doris muricata , Muller 
(Zool. Dan.), they were noted down as being certainly distinct from it : — in 
being of a more elongate shape, in having the tubercles differently formed, 
and, in proportion to the dimensions of the body, their being not more 
than half the size of those of D. muricata. Messrs. Alder and Hancock 
made the following comparative observations : “ Comparing your D. 
muricata [a species they had not seen before] with our D. aspera and 
your D. Ulidiana, we come to the conclusion, so far as we can judge from 
specimens in spirits, that these three are distinct, though nearly allied, 
species. D. Ulidiana differs from D. muricata in its much larger size, 
and longer and more depressed form. The tubercles appear to be more 
depressed, and the branchial plumes larger. From D. aspera it differs 
also in size and shape ; in having larger tubercles, the cloak narrower, 
and the foot broader.” 
D. obvelata, Johnston. 
Mr. Hyndman procured a specimen of this Doris on Fuci at Skerries, 
Dublin coast. On its being submitted to the inspection of Mr. Alder, by 
whom the original specimen described by Dr. Johnston was discovered 
in Berwick Bay, he remarked that the species “ appears to be pretty ge- 
nerally diffused, but nowhere common.” He had obtained it last summer 
in Rothesay Bay. 
Doris muricata, Mull. 
I have not unfrequently taken this minute species when dredging (accom- 
panied by Mr. Hyndman) in the loughs of Strangford and Belfast ; it was 
generally adhering to the leaves of tangle ( Laminaria digitata). Muller 
describes it as 5 lines long by 3 broad : my specimens were all even under 
this size. The D. muricata has hitherto been unnoticed in the British seas. 
D. aspera , Aid. and Hanc. 
Very young examples of a Doris , and most probably (according to Mr. 
