NOTE (C.)

CEYLON FISHES.

(Memorandum, by Professor Huxley.)

The large series of beautifully coloured drawings of the fishes of Ceylon, which has been submitted to my inspection, possesses an unusual value for several reasons.

The fishes, it appears, were all captured at Colombo, and even had those from other parts of Ceylon been added, the geographical area would not have been very extended. Nevertheless there are more than 600 drawings, and though it is possible that some of these represent varieties in different stages of growth of the same species, I have not been able to find definite evidence of the fact in any of those groups which I have particularly tested. If, however, these drawings represent six hundred distinct species of fish, they constitute, so far as I know, the largest collection of fish from one locality in existence.

The number of known British fishes may be safely assumed to be less than 250, and Mr. Yarrell enumerates only 226, Dr. Cantor's valuable work on Malayan fishes enumerates not more than 238, while Dr. Russell has figured only 200 from Coromandel. Even the enormous area of the Chinese and Japanese seas has as yet not yielded 800 species of fishes.

The large extent of the collection alone, then, renders it of great importance; but its value is immeasurably enhanced by two circumstances,—the first, that every drawing was made while the fish retained all that vividness of colouring which becomes lost so soon after its removal from its native element; second, that when the sketch was finished its subject was carefully labelled, preserved in spirits, and forwarded to England, so that at the present moment the original of every drawing can be subjected to anatomical examination, and compared with already named species.

Under these circumstances, I do not hesitate to say that the collection is one of the most valuable in existence, and might, if properly worked out, become a large and secure foundation for all future investigation into the ichthyology of the Indian Ocean.

It would be very hazardous to express an opinion as to the novelty or otherwise of the species and genera figured without the study of the specimens themselves, as the specific distinctions of fish are for the most part based upon character; the fin-rays, teeth, the operculum, &c., which can only be made out by close and careful examination of the object, and cannot be represented in ordinary drawings however accurate.

There are certain groups of fish, however, whose family traits are so marked as to render it almost impossible to mistake even their portraits, and hence I may venture, without fear of being far wrong, upon a few remarks as to the general features of the ichthyological fauna of Ceylon.

In our own seas rather less than a tenth of the species of fishes belong to the cod tribe. I have not found one represented in these drawings, nor do either Russell or Cantor mention any in the surrounding seas, and the result is in general harmony with the known laws of distribution of these most useful of fishes.

On the other hand, the mackerel family, including the tunnies, the bonitos, the dories, the horse-mackerels, &c., which form not more than one sixteenth of our own fish fauna, but which are known to increase their proportion in hot climates, appear in wonderful variety of form and colour, and constitute not less than one fifth of the whole of the species of Ceylon fish. In Russell's catalogue they form less than one fifth, in Cantor's less than one sixth.

Marine and other siluroid fishes, a group represented on the continent of Europe, but doubtfully, if at all, in this country, constitute one twentieth of the Ceylon fishes. In Russell's and Cantor's lists they form about one thirtieth of the whole.

The sharks and rays form about one seventh of our own fish fauna. They constitute about one tenth or one eleventh of Russell and Cantor's lists, while among these Ceylon drawings I find not more than twenty, or about one thirtieth of the whole, which can be referred to this group of fishes. It must be extremely interesting to know whether this circumstance is owing to accident, or to the local peculiarities of Colombo, or whether the fauna of Ceylon really is deficient in such fishes.

The like exceptional character is to be noticed in the proportion of the tribe of flat fishes, or Pleuronectidæ. Soles, turbots, and the like, form nearly one twelfth of our own fishes. Both Cantor and Russell give the flat fishes as making one twenty-second part of their collection, while in the whole 600 Ceylon drawings I can find but five Pleuronectidæ.

When this great collection has been carefully studied, I doubt not that many more interesting distributional facts will be evolved.

Since receiving this note from Professor Huxley, the drawings in question have been submitted to Dr. Gray, of the British Museum, and that eminent naturalist, after a careful analysis, has favoured me with the following memorandum of the fishes they exhibit, numerically contrasting them with those of China and Japan, so far as we are acquainted with the ichthyology of those seas:—

	Ceylon	China and Japan.
Cartilaginea.
Squali	12	15
Raiæ	19	20
Sturiones	0	1
Ostinopterygii.
Plectognathi.
tetraodontidæ	10	21
balistidæ	9	19
Lophobranchii
syngnathidæ	2	2
pegasidæ	0	3
Ctenobranchii
lophidæ	1	3
Cyclopodii.
echeneidæ	0	1
cyclopteridæ	0	1
gobidæ	7	35
Percini.
callionymidæ	0	7
uranoscopidæ	0	7
cottidæ	0	13
triglidæ	11	37
polynemidæ	12	3
mullidæ	1	7
percidæ	26	12
berycidæ	0	5
sillaginidæ	3	1
sciænidæ	19	13
hæmulinidæ	6	12
serranidæ	31	38
theraponidæ	8	20
cirrhitidæ	0	2
mænidiæ	37	25
sparidæ	16	17
acanthuridæ	14	6
chætodontidæ	25	21
fistularidæ	2	3
Periodopharyngi.
mugilidæ	5	7
anabantidæ	6	15
pomacentridæ	10	11
Pharyngognathi.
labridæ	16	35
scomberesocidæ	13	6
blenniidæ	3	8
Scomberina.
zeidæ	0	2
sphyrænidæ	5	4
scomberidæ	118	62
xiphiidæ	0	1
cepolidæ	0	5
Heterosomata.
platessoideæ	5	22
siluridæ	31	24
cyprinidæ	19	52
scopelinidæ	2	7
salmonidæ	0	1
clupeidæ	43	22
gadidæ	0	2
macruridæ	1	0
Apodes.
anguillidæ	8	12
murænidæ	8	6
sphagebranchidæ	8	10