324 
SCANDINAVIAN FISHES. 
in the same space Regalecus capensis should only possess 163 rays; 
and in a specimen of Regalecus glesne from Bohuslan this space should 
presumably contain only 103 rays. Thus we might here expect to 
find a specific distinction expressed without difficulty; but in fishes 
of so loose a structure as these, and considering that in Regalecus 
glesne we are compelled to recognise a variation in the rays of the 
dorsal fin so considerable as to range between 200 and 400, the dif- 
ference in the degree of contraction of the body may considerably 
affect the results arrived at, and the individual variations render the 
character worthless. As a general rule we may reasonably assume 
that the rays of the dorsal fin are more densely set in young speci- 
mens; but in the largest 'example known, Lindroth’s specimen from 
Hitteren, there are 47 rays in a space which in the Royal Museum’s 
smaller specimen, from Bohuslan, contains only 40 rays, and accord- 
ing to Collett, in the Stavanger specimen (1881 — Stavanger Mu- 
seum), which in size was probably almost exactly intermediate between 
these two specimens, there are on an average 43 rays in a similar 
portion of the dorsal fin. 
The relation between these three specimens thus contradicts the 
above rule; and a further example of the individual variations may 
be found in the Regalecus from the waters between the coasts of 
Tasmania and Victoria, in May 1878, which specimen McCoy (1. c.) 
referred to the same species as the Atlantic King of the Herrings, 
assuming that the identity of the species may be defended, as seems 
not improbable. This Australian Regalecus was only 414 cm. long, 
and only an insignificant part of the tail was wanting (the last re- 
maining ray of the dorsal fin was only 2 mm. long and the tail, at 
the point of fracture, only 13 mm. deep). It was thus at least 1 
metre shorter, though more nearly perfect, than the Hitteren specimen; 
but it had 406 dorsal fin rays, in addition to the 17 rays of the high 
occipital fin. In the shape of the body — which was, however, con- 
siderably shallower, a characteristic which McCoy supposes to belong 
to the male — in the coloration and in other respects “ this Regalecus 
so closely resembles the Atlantic species that it is only our insufficient 
knowledge of the latter species that calls for caution in the identi- 
fication of two species from localities so distant. 
We may still acknowledge the truth of Nilsson’s words : “It is 
impossible strictly to define the distinction between the species of this 
genus”. But it seems most probable that as yet we know only one 
species of the genus; and the fragmentary knowledge we possess of 
the adult stages of this species — no entire specimen of the Atlantic 
Regalecus glesne has yet been scientifically examined — may safely 
be supplemented from the better-preserved specimens of the Mediter- 
ranean and Australia. 
The Royal Museum possesses the remains of two specimens of 
Regalecus glesne. Of the first specimen, which was found on the 12th 
of August, 1797, off the island of Hitteren, near Trondhjem, and 
which was the original of Lindroth’s description and figure (1. c.) of 
Gymnetrus Grillii, there is left only the skin of the left side behind 
the head and the ray of the left ventral fin. This part, which was 
stuffed by Lindroth for Grill’s museum at Soderfors, is nailed to a 
board. The head and the dorsal fin are artificial, as they are shown by 
Lindroth in his figure of the stuffed specimen. This example is re- 
markable in several respects. It is the longest specimen hitherto pre- 
served and examined. The number of rays in the dorsal fin is greater, 
and the vent is situated farther forward, relatively to the length of 
the body, than in any other Atlantic specimen on record. The last 
two characteristics may thus be interpreted as expressions of the 
changes of growth; but the difference between it and the other At- 
lantic specimens in these respects is so great that some standard by 
which to test the correctness of the description, may well be required, 
and the specimen fortunately offers us one, even in its incomplete 
state. The interspinal bones are still to be found at the dorsal edge, 
throughout the greater part of the length of the body, and, posteriorly 
at least, are so distinct that they may be counted without difficulty. 
The total length of the base of the dorsal fin left is 515 cm. The 
part occupied by the last 100 interspinal bones measures 945 mm., 
by the next 100 in front of them 1,305 min., and by the next 100 
1,505 mm. The remaining 1,395 mm., where the interspinal bones are 
now partly indistinct, can hardly have contained less than 106 rays, the 
number of artificial rays set there by Lindroth. It is, therefore, highly 
probable that Lindroth’s statement that the dorsal fin contained 406 
rays, is based on his examination of the fresh specimen, just as it was 
when he received it and before the dorsal fin was lost. This assump- 
tion finds strong support in McCoy’s description of the Australian Rega- 
lecus >, which had still more rays in the dorsal fin. Again, with re- 
gard to the position of the vent Lindroth gives a definite measurement 
(4 Sw. ft. 7 in. = 1,361 mm.) of the distance between it and the 
head, a statement which almost exactly applies to the stuffed skin, 
where the vent itself is 25 mm. long, and is stopped with red putty. 
This distance is indeed less in proportion to the length of the body 
than in any other specimen known (nearly 25 1 /<> %, instead of the 
usual average 34 * */, /); but in proportion to the depth of the body 
as given by Lindroth (25 1 /., % of this distance) it corresponds fairly 
closely to the same measurement in several of the specimens best 
known in this respect*. 
The second specimen in the possession of the Royal Museum is 
the only Swedish specimen of Regalecus glesne discovered up to the 
present date. It was found on the 28th of March, 1879, about 3 
miles west of Koster, on the shore of an islet called Burholm, and 
secured for the Museum by Mr. G. v. Yhlen, Inspector of Fisheries. 
The greatest depth of the body, according to Coastguard Mattson’s 
statement, was a little more than a foot (3 dm.) and the thickness 
about 4 in. (1 dm.). The length was 2 5 1 / 4 ft. (?). The colour was 
“grayish on the sides and white on the back, covered with a bright 
dust’’. A fin 3 in. (75 mm.) high ran from the occiput to the tail. 
When the specimen was secured for the Royal Museum, however, it 
had been considerably damaged by the surf and the ravages of birds. 
The upper part of the black forehead, with the groove for the nasal 
processes of the intermaxillary bones, is, however, preserved, and on 
the occiput we can find traces of the anterior fin-rays, the first of 
which points in a forward direction and is set at the end of the 
groove just mentioned. The rest of the head is crushed to pieces, 
and the nasal regiqn, with all the jaw-bones, is wanting. The re- 
mainder of the body from the first ray of the dorsal (occipital) fin 
is 245 cm. in length, and the greatest depth, which occurs at a dis- 
tance of from 5 to 11 dm. from this ray, is 29 x / 2 cm. At this 
point the lateral line (fig. 88, a) lies at a distance of 70 mm. from 
the ventral edge and 226 mm. from the dorsal. The greatest thick- 
ness is now only 36 min.; and, according to Mattson’s statement, the 
body has thus shrunk to 1 / 3 of its original thickness. The gill-rakers, 
42 in number, may be counted on the first branchial arch. They are 
a According to McCoy’s measurements the length of the head is greater than the depth of the body; but the figures show that he 
took the length of the head when the mouth was protruded. 
* The greatest depth of the body in % of the distance between the head and the vent measures, according to published statements, 
in the specimen from North Fjord (1855 — Bergen Museum) 24'9 
,, ,, ,, ,, Langesund (1822 — -Christiania Museum) 26'5 
,, ,, ,, ,, Grovie (1844, see Richardson, Suppl. to Yarr., Brit. Fish.) 261 
,, ,. ,, ,, the Cape of Good Hope (1868, see Layard, Proc. Zool. Soc.) 25'9 
