1198 
SCANDINAVIAN FISHES. 
the pterygoid cartilage passes into a narrow cartilage 
which has been named the mandibulohyoid, and on the 
inner side of the last-mentioned cartilage, close to and 
below the outside of the auditory capsule, lies a small, 
narrow, oval hole ( fenestra mandibulo-Jiyoidea, q). The 
small part (Parker’s “pedicle”) in front of this hole 
answers to the upper end of the suspensorium ; and 
the part ( hyomandibidare ) that bounds the hole behind 
Fig. 356. Cartilaginous framework of the tongue in Myxine gluti- 
nosa, with the teeth in position, seen from above, X 5. 
After Parker. 
a, b, basihyal cartilages; c, supralingual cartilage; d , supralingual 
teeth; e, basibranchial cartilage. 
to the head of the hyoid arch. On the outside of the 
anterior lateral fenestra there lie, behind the pterygoi- 
deum a broad plate of hard cartilage, answering to the 
quadrate region ( quadratum , r), and behind this again 
a soft cartilage ( regio symplectica, s ), which forms the 
posterior limit of the anterior lateral fenestra and passes 
inwards, behind the hard mandibulo-hyoideum, into 
another soft cartilage ( interhyoideum , t) and its conti- 
nuation ( epihyoideum , u). These last-mentioned carti- 
lages emit in an outward direction two soft cartilagi- 
nous arches, the anterior (whose upper part is named 
the ceratohyoideum (v), the extero-inferior part the 
hypohyoideum ) bending outwards and downwards and 
attaching itself to a hard cartilage ( basihyoidewn ), the 
posterior ( epibranchiale primum , x) curving downwards 
and forwards and attaching itself annularly to the sym- 
plectic region, together with which it surrounds a large 
hole ( fenestra lateralis posterior, y). On the inside of, 
but not directly continuous with, the interhyoideum, 
epihyoideum, and symplectic region, lies a cartilage 
which answers to the first pharyngobranchial bone 0), 
and which with its hard, clavate, anterior end, close 
to the inner margin of the quadratum, occupies the 
posterior part of the anterior lateral cavity and with 
its soft, tapering, posterior end reaches a little way 
behind the epibranchial cartilage. The second branchial 
arch ( pharyngo-branchiale secundum, d) is represented 
only by its pharyngeal, upper part, which is here com- 
posed of a few medially connected, singularly formed, 
branched rods of soft cartilage, embedded in that fold 
of the palatine mucous membrane which lies behind 
the pharyngeal aperture of the nasal duct. 
The lingual apparatus of Myxine displays an espe- 
cially powerful development and is furnished with large 
cartilages both hard and soft (fig. 356). Thus there 
are four hard basihyal cartilages {a, b) and on their 
upper surface a part consisting of several cartilages 
(the supralingual cartilages , c ), which bear the power- 
fully developed supralingual teeth {d). Backwards from 
the basihyal cartilage runs a dorsally grooved rod of 
fibrocartilage (the basibranchial cartilage, e ), which ex- 
tends back to the region of the gill-sacs. 
The muscular system of Myxine exhibits about 
the same developmental type as that of Petromyzon 
and even, in the main, as that of the other piscine 
orders, i. e. on each side a “great lateral muscle ” di- 
vided into very numerous parts {myomeres) by septa 
of connective tissue ( myocommata ), and thus showing a 
segmental arrangement, though the axial skeleton is 
not segmented, and two ventral muscles. There being 
no extremities, or lateral fins, the muscles belonging 
to them are also wanting; but the head, on the other 
hand, contains rather numerous singular muscles, which 
