LAMPERN. 
1193 
tills than in Petr. Planeri. Its length varies here too 
between about 10 and 8 % of that of the body. The 
anal aperture also occupies the same position as in t he 
Sea Lamprey but the urogenital papilla is generally 
more developed, especially in Petromyson Planeri , and 
longest and most pointed (projecting far back), as 
usual, in the males. Besides tins sexual character may 
be observed during the breeding season, especially in 
the females, an hydropical tumidity of the skin (fig. 
349), in particular round the anus and along the anal 
fin-ridge, which is sometimes considerably elevated at 
this season, as well as along the base and in front of 
the second dorsal fin. 
The coloration differs from that of the preceding 
species in its monotony, being without sharply defined 
spots, and as a rule on the back steel-blue or darker, 
on the belly white, with a silvery lustre on the sides 
of the body. Yet it varies with the age of the fish, 
the season of the year, and the locality. In fresh water 
and with age the back becomes greener, and the belly 
assumes a muddier tone. The fins are either transparent, 
grayish white, or, in old specimens, brownish. The 
Prides are entirely destitute of silvery lustre and some- 
times greenish yellow, sometimes bluish green. Our 
figures of Prides, as well as of the Lampern, are painted 
from living specimens taken by Professor Retzius at 
Elfkarleby early in October. 
The Lampern is dispersed throughout Europe, 
Northern Asia, and Japan, as well as the northern re- 
gions of North America together with Greenland. Theel 
and Trybom brought home Prides of this species from 
the Yenisei; Gunther referred the Petromyson japoni- 
cus described by Martens" to the same species as our 
Lampern; Petromyson pkmbeus ( cibarius ) and Petr, au- 
reus from the west coast of North America have ap- 
parently no greater claim, judging by the descriptions, 
to a specific rank; and from Southern Greenland, ac- 
cording to Lutken, the Museum of Copenhagen has re- 
ceived two specimens of Petromyson fluviatilis. Through- 
out Sweden this species occurs in both varieties, but 
seems to be less common in the west than in the east, 
besides which it has long been known that the more 
typical form is commonest and largest in the Baltic and 
the rivers of Northern Sweden. In Norway the last- 
a Wiegtn. Arch. XXXIV, p. 3. 
b Not adduced from Greece, however, by Apostolides. 
c Ofvers. Vet. Akad. Fork. 1876, No. 3, p. 140. 
d Nord. Aarsskr. Fisk. 1883, p. 307. 
mentioned form, according to Collett, is very rare and 
has been met with only in Christiania Fjord, but Petro- 
myson Planeri is said to be common enough south of 
the Dovrefjeld, where it attains, according to Rasch, a 
length of at least 3 dm. North of the Dovrefjeld the 
species has not been found; but Mela adduces it from 
Varanger Fjord, and it has long been known from the 
White Sea and the rivers of Northern Russia. In Den- 
mark it has been met with both on the islands and in 
Jutland. In the Sound it is no rarity. On Bornholm, 
according to Feddersen, only the smaller form has been 
found. In Russia, Germany, the Netherlands, Southern 
Europe 6 , and the British Islands it is as common as in 
Scandinavia, in some places perhaps commoner. Ac- 
cording to Fatio it is unable to pass the great falls of 
the Rhine and Rhone, being wanting both in Lake Con- 
stance and the Lake of Geneva. In Scandinavia, on 
the other hand, each of the forms occurs both in Lake 
Wener, above Trollhattan, and in Lake Wetter. Nearest 
the sources of the brooks and in small collections of 
water the smaller form has its home; the larger keeps 
to the lower courses of the rivers and, in the lakes, 
to the outlets of the brooks. How high the Lampern 
ascends in the mountain regions of Scandinavia, is 
scarcely known as yet. Olsson 0 says that both Lam- 
perns and Prides are common in the southern part of 
Stroms Vattudal (Jemtland), though they do not ascend 
the streams flowing thither. According to Trybom' 6 
o 
Prides 11 — 13 cm. long have been found at Asele 
(Angerman Elf, 64° 10' N. lat.; 300 m. above the sea- 
level), on flax placed in the river to steep; and similar 
specimens are sometimes taken, it is stated, in Lake 
Storlogcle (Logde Elf). Lilljeborg found Petromyson 
Planeri at Karesuando (Muonio Elf, 68° 25' N. lat.; 320 
m. above the sea-level). Fatio sets the limit to the 
ascent of the Lampern in Switzerland at about 600 to 
700 in. above the level of the sea. 
Tenacious of life and greedy of prey, the Lampern 
has the same habits as the preceding species. Its man- 
ner of life in the sea is hardly known, for it is met 
with too seldom in salt water. Baltic specimens have 
been found to have the intestinal canal (stomach and 
spiral intestine) filled to distension with a pulpy mass, 
in which we could distinguish in one specimen morsels 
