SERIALLY STRIPED HADDOCK IN NEW BRUNSWICK 89 
SESSIONAL PAPER No. 38a 
eolour in a vast number of animals. Professor McIntosh’s description of the young 
cod is interesting: “The minute larval cod escapes from the egg,” says that authority, 
“marked by a series of transverse bars, then the black pigment is re-arranged longi- 
tudinally along the dorsum as it swims high in the water. To this is added, by and by, 
vellow pigment, causing (with the black) a greenish hue. When it seeks the rocky 
margins it becomes boldly tessellated..... . the larval haddock has no transverse bars, 
though bred side by side with the cod; but the dorsal band of black pigment is 
developed in the next stage (post-larval). Instead of seeking the shore the little 
haddock keeps to deep water, and it soon develops the characteristic bold touches of 
black on the sides above the pectoral region.” (5, p. 237.) 
But the presence of stripes or transverse bars of colour is not confined to pelagic 
larval fishes out in the open sea, like cod, ete., for even familiar shore fishes in their 
voung stages often show this striking arrangement of pigment. Thus I find in the 
common cunner, or sea perch (Tautogolabrus adspersus) so abundant along our eastern 
shores, the young forms exhibit the transverse bars, eight or nine dark ochre bands 
richly spotted with black dots, extending from the head region to the base of the tail, 
when the fish is barely half-an-inch long (13.5 mm.). See Plate IX., fig. 8. The 
young salmon of the Pacific and Atlantic rivers, as is well known, show definite stripes. 
The young sockeye or red salmon, Oncorhynchus nerka, seven months old, shows eleven 
to twelve bars, and the Atlantic salmon parr, Salmo salar, shows nine or ten such bars 
or stripes. (Plate IX., figs. 6 and 7). The pigment spots, of which these coloured 
bands and patches are composed, are rounded particles of naked protoplasm, packed 
with coloured granules and capable of contracting and expanding in stellate form. 
The centre or nucleus is often more deeply coloured than the rest of the corpuscle. A 
group of such pigment corpuscles or cells from the skin of a young fish 4 of an inch 
long (a larval Gastrosteus aculeatus 8-9 mm.) are shown on Plate IX., fig. 9. These 
coloured particles move with such facility under the influence of lght or electrical, 
chemical and nervous stimulh, that the arrangements of colour may undergo very rapid 
changes. The tranformation of spots into bars, by serial aggregation, or the separation 
of transverse stripes into separate rounded patches, can be readily understood. But the 
most interesting point that arises in connection with these striped haddocks is this, 
that they demonstrate the resumption at times of an arrangement of colour, which 
must have ancestrally applied to the species as a whole; but now appears only errati- 
cally and locally. The causes of such ancestral reminiscence are obscure and little 
understood. Ancestral traits, long lost, even amongst human beings, occasionally 
reappear, and amongst such fishes as the haddock, an ancestral, long-lost arrangement 
of external coloration is revived at times, and may even become marked as a not 
infrequent local variation as in the striped Passamaquoddy haddocks. 
The black stripes have disappeared altogether in the adult cod; but a remnant 
persists in the ordinary haddock as a black blotch in the shoulder region, the dark 
“thumb-mark.” Such blotches or thumb-marks, when repeated serially, must be 
regarded therefore as atavistic, a reappearance of an ancestral trait or feature, which 
in most specimens has practically disappeared. 
