PIKE. 
1001 
its two halves are joined in front (mb), at the sym- 
physis, merely by cartilage instead of the ordinary 
firm suture. 
The long maxillaries ( mx ), which are somewhat 
curved and twisted, are toothless, and the single or 
sometimes (in front) double row of intermaxillary teeth 
are not very large; but all the greater is the size of 
the teeth on the head ( vom ) of the vomer, in the inner 
rows on the palatines (pi), and, above all, in the lower 
jaw (de). In the long, posteriorly pointed patch of 
teeth that occupies the shaft ( vonip ) of the vomer, ex- 
tending back to a line with the nasal cavities, the 
dense teeth decrease in size behind, a diminution which 
also appears, both outwards and backwards, in the some- 
what broader card of palatine teeth, which extends a 
little further back than the vomerine card. The man- 
dibular teeth of young Pike are set throughout in one 
row; in large Pike there are two rows at the extreme 
front, both being incurved (recurved) nearest to the 
symphysis, but only one row throughout the rest of 
the jaw margin. The front teeth are comparatively 
small, about twice as large as the intermaxillary teeth; 
but the size increases backwards, while the teeth be- 
come more scattered, the posterior two-thirds of the 
jaw margin being armed with only about 6 large ca- 
nines. Among these canines the middle ones are the 
largest, being of so considerable a size that in Pike 9 
dm. long’ the largest mandibular tooth measures together 
with its base 19 mm. and above the gum 14 mm. 
The tongue is cartilaginous, somewhat broader in front, 
but incised at the truncate tip. The hind part of its 
lingual bone and the three copular bones (the first and 
largest of which is formed by the coalescence of two), 
are set with dense cards of small teeth. The roof of 
the pharynx is armed with two pairs of cards, on the 
upper pharyngeals, containing teeth about equal in size 
to the foremost in the lower jaw, the anterior cards 
pointed in front, and both cards together of about the 
same size and form as either of the two cards on the 
lower pharyngeals. The last-mentioned bones are slen- 
der (resembling branchial arches), but furnished on the 
posterior inward side with an elevated, flat process, 
over which the card of teeth extends, being thus raised 
free above the hind part of the pharyngeal itself. All 
the hones already enumerated in the mouth and pha- 
rynx may be dentigerous in most of the Teleosts; but 
in the Pike we further find that the gill-rakers, on the 
front of the branchial arches, are transformed into dense 
cards of teeth, divided into quadrilateral or rounded 
(verrucose) groups, and containing teeth about equal 
in size to the intermaxillary ones. The number of the 
teeth is thus augmented so considerably that Keoyer 
succeeded in counting “ certainly more than three thou- 
sand teeth” in the mouth and pharynx of a Pike. All 
the teeth are ophidian in type, pointed, for the most 
part curved, rigid in an outward direction, flexible to- 
wards the interior of the mouth, with the tip directed 
inwards and backwards, thus affording a ready ingress 
to the prey, but preventing its egress. Exceptional in 
form are the straight small teeth on the branchial ar- 
ches, and the largest canines in the lower jaw, which 
are also straight, but dagger-shaped and two-edged. 
The number of the branchiostegal rays varies be- 
tween 13 and 16, being not unfrequently different on 
either side. All of them are sabre-curved, the posterior 
sharp, the anterior rather more terete. The anterior 
(lower) 6 or 7 are set on the ceratohyoid bone, and 
are somewhat separated from the posterior (usually 8), 
which belong to the epihyoid. The branchiostegal mem- 
branes are free and separate underneath to the root of 
the tongue, where they are attached, the very extre- 
mities crossing each other. This arrangement further 
contributes to the distensibility of the pharynx. 
The top of the head is flat, with a concavity be- 
tween the eyes. These are large", oval 5 , rather far 
apart 0 , and set high, about half-way along the head A 
Above their anterior part projects a semi-elliptical or 
rounded quadrilateral bone (fig. 253, spo) that calls to 
mind the superciliary shield in birds of prey, and gives 
the Pike a similar fierce and savage look. The nasal 
cavities are large, and lie just in front of the eyes, 
each containing two apertures, the anterior round, the 
posterior furnished with a rounded dermal lid, origi- 
nating from the fairly broad ridge of skin between them. 
° The longitudinal diameter of the eyes measures in the young about */ 5 , in Pike 4 — 5 dm. long about J / 8 — 1 / 9 , of the length 
of the head. 
b The vertical diameter of the eyes is about 80 — 85 % of the longitudinal. 
c The interorbital width at the middle of the eyes is about 1 / s (19 — 21 %) of the length of the head. 
d The length of the snout is about 42 (sometimes 40) — 45 %, and the postorbital length about 43 (in the fry 37)— 46 %, of the 
length of the head. 
