554 
CAPTAIN E. W. SHANN ON 
(i) Adductor superficialis (add.s.). 
The main mass of this muscle arises on the outer border of the scapula and is 
inserted into the underlying adductor profundus. The first two adductor bundles 
(preaxial) are not divided into layers and may be described, as in Selachians, as 
belonging entirely to the superficial series. The first, arising from the postero-external 
border of the scapula, opposite to the upper third of the coraco-branchialis, runs 
downwards and slightly outwards' to its insertion on the inner upper border of the 
propterygium ; as it fills the axil of the fin its shape conforms approximately to that 
of a wedge. The second in Callorhynchus follows a parallel course and finds insertion 
on the propterygial radial ; but in Chimeera we meet with a very striking modification. 
The insertion is strap-like, partly tendinous, and occurs on the proximal fifth only 
of the propterygial radial ; from here the fibres run almost vertically to take origin 
not only from the outer surface of the scapula (opposite to the insertion of the l.p.), 
but also from the fascia covering the r.l.v.p. as far up as the lateral line. (See 
fig. 6.) 
The third superficial bundle has a distinct origin in the cavity of the scapula near 
the preaxial end of the glenoid border ; it is very slender and soon fuses with the 
much stouter first bundle of the deep series, which in turn is inserted into the distal 
portion of the propterygial radial. The remaining thirty bundles are divided into 
two groups, of which the preaxial, as in Selachians, is overlapped near its origin by 
the postaxial. The preaxial group consists of twenty-one bundles in the example 
figured ; these arise from a bowl-like cavity in the coraco-scapular region of the 
girdle opposite to the middle of the glenoid border. The bundles are by no means 
distinct in the region of origin, and the muscle is characterised by the great depth 
in comparison to its width. As the fibres pass outwards they spread laterally, and, 
as a consequence, the mass becomes shallower. They begin now to be collected into 
bundles, which become more and more distinct as the distal extremity of the muscle 
is reached. The deepest fibres, when they reach the level of the basal cartilages of 
the fin, blend with the underlying adductor profundus. In fig. 10 the superficial 
bundles appear to be inserted entirely at the distal extremity of the corresponding 
deep bundles ; it should be pointed out that this is a diagrammatic representation, 
the remainder of the insertion (extending almost the whole length of the add.p.) 
being omitted for the sake of clearness. The remaining nine bundles comprise the 
postaxial group. These arise from the outer border of the scapula, a short distance 
above the origin of the preaxial group, and in their outward passage obscure the 
latter. 
(ii) Adductor profundus (add.p.). 
This muscle is composed of bundles which correspond in number and relative 
position to those of the superficial series described above, with the exception of the 
two preaxial ones, which, as already stated, have no representatives in the lower 
