across the mesial surface of th e hind end of Meckel’s cartilage and is inserted on the mesial surface
of th e articular ventral to th e cartilage. The antero-dorsal tendon tu rn s forward and is inserted
on the tendinous formation th a t covers the mesial surface of A,*,.
The mandibular portion, Affl, of th e adductor muscle, arises wholly on th e mesial surface
of the mandible, its fibers converging toward and having the ir insertions on a tendinous formation
which largely covers th e mesial surface of th e muscle. A p a rt of th e fibers of this tendinous formation
are collected and separated to join th e antero-dorsal tendon of A2A3, th e remaining fibers running
directly backward, mesial to all the tendons of th e muscle, and having their insertions* as a broad
tendinous band, on th e preopercular, near its ventral end. In Scomber this la tte r tendon is inserted
by two heads, one on the preopercular and th e other on th e quadrate, th e rami mandibularis externus
and internus passing between the two heads of th e tendon (Allis, ’03, p. 194).
The levator arcus palatini arises from the roughened lateral corner of th e sphenotic. Running
downward from there, and spreading slightly forward and backward, it separates into superficial
and deeper portions. The superficial portion passes internal to th e superficial division, Al5 of th e
adductor mandibulae, between it and A3, and then between A2 and A3, and has its insertion on
th e external one of th e two flanges on the hind edge of th e metapterygoid, and on adjacent
portions of th e hyomandibular and preopercular. Some of its fibers are also apparently
inserted in th e membrane th a t covers th e external surface of th e muscle A3. A strong tendon is imbedded
in this superficial portion of th e levator, extends from th e sphenotic to th e metapterygoid,
and gives insertion or origin to certain of th e fibers of the muscle. The deeper portion of th e muscle
passes between the two flanges on th e hind edge of the metapterygoid and has its insertion
on those flanges and on th e two membranes th a t connect th e flanges with th e anterior edge of th e
hyomandibular. The ventral end of the internal one of these two membranes has a strong attachment
to th e internal surface of th e dorsal end of the interhyal, and it would seem as if th e muscle must
have some action on th a t bone. The two portions of th e levator correspond respectively to th e
superficial and deeper portions of th e muscle of Amia.
5. L A T E R O - S E N S O R Y C A N A L S .
The primary tubes of the latero-sensory canals of Scorpaena, in every case examined, leave
the bones to which they are related as simple and single tubes, b u t, in the overlying dermal tissues,
most of them branch repeatedly giving rise to large and often complicated dendritic systems which
open on th e outer surface by small and often numerous pores. Certain of these dendritic systems,
belonging to different canals, interanastomose, thus secondarily connecting primarily independent
canals, and giving rise to conditions th a t might, in a superficial examination, be considered as marked
irregularities in th e course of those canals.
The main infraorbital canal begins a t a group of pores th a t lies ventro-lateral to the interval
between th e two nasal apertures. In the two specimens th a t were carefully examined in this connection,
this group was subcircular in outline and contained from 15 to 18 pores; and on one side of
one of these two specimens certain of th e pores of th e group seemed to have anastomosed with certain
pores of the second dendritic system of the supraorbital canal, th u s apparently establishing a
communication between those two canals, the communicating canal passing between the nasal apertures.
The group of pores belongs to the first d endritic system of the line, and th e tru n k of the system enters
th e lachrymal bone by th e single large aperture on the dorso-anterior edge of th a t bone. The canal
then traverses th e lachrymal, giving off two primary tubes in its course, these tubes opening on the
outer surface b y small groups of pores which lie one between the anterior and next posterior spine
of th e bone, and th e other between this la tte r spine and th e next posterior one. The fourth tube of
th e line leaves the canal as it passes from th e lachrymal into th e first suborbital, and the fifth tube
as it passes from th a t bone into th e second suborbital, these tubes both opening on the outer surface
b y small groups of pores th a t lie ventral to the canal.
In th e second suborbital (third infraorbital) the canal runs backward nearly to the hind edge
of th e bone, where it issues from th e bone on its external surface and ends, having given off one
primary tube in its course. This la tte r tube is the 6 th. tube of the line, the canal ending in a terminal
tube which represents one half of th e 7 th. tu b e of the line," as will b e further explained below. These
two tubes lie ra th e r close together, near th e hind edge of the bone, the 6 th. tube directed postero-
ventrally and th e 7 th. one postero-dorsally. Both tubes open on the outer surface by a group of
pores, and c ertain pores of th e 7 th. group had secondarily fused, in all th e several specimens examined,
with certain pores of th e penultimate dendritic system of the preopercular canal, a dermal communication
between the hind end of th e suborbital section of the main infraorbital canal and th e preopercular
canal th u s here being established. This communication is large and important, and one not
thoroughly conversant with this subject might naturally be led to say, as Garman (’99) has said of
Ectreposebastes imus, th a t th e postorbital portion of th e main infraorbital canal and th e dorsal
portion of the preopercular canal were here „reduced to a single c a n a l ||| This however would certainly
be, if said of Scorpaena, and must also be of Ectreposebastes, a most misleading statement
of the case, for the two main canals themselves do not in any sense here run into each other, a certain
pore or pores of a dendritic system of one of them simply anastomosing, secondarily, with a
certain pore or pores of a dendritic system of the other.
Beyond the 7 th. primary tube, the main infraorbital canal is interrupted, the next posterior
section of th e canal being enclosed in th e little postorbital ossicle, and n ot having any direct connection
with th e suborbital portion of th e line. The 7 th . tube of the line is thus the terminal tube of an
anterior, suborbital portion of the line, and is th e anterior half, only, of what would be the 7 th.
primary tube of a continuous canal. The other half of this primary tube lies directly behind th e eye,
a t the ventral edge of th e little postorbital ossicle, and forms the anterior tube of the postorbital
section of th e canal. In some specimens the dendritic system formed by the repeated subdivisions
of this posterior half of th e 7 th. primary tube seemed to be in secondary communication with the
penultimate system of th e preopercular canal, b ut, in the one wholly satisfactory preparation
made, this connection did n o t exist. The dissection necessary to establish this is a difficult and
delicate one, and the use of injecting fluids is usually misleading, for th e delicate walls of the tubes
are easily broken down and artificial connections thus established.
Starting from th e posterior half tube of the 7 th. primary system of the line, the canal runs
upward through th e postorbital ossicle and then traverses th e relatively wide interval between this
ossicle and the postfrontal bone, there lying immediately beneath the th in dermis. From this p a rt
of th e canal th e 8 th. primary system of th e line arises, this system being a large and complicated
one, and having much more the appearance of two half systems th a t have secondarily anastomosed
th an of two half tubes th a t have completely fused to form a single tu b e and system. The branches
of this system extend backward across the cheek, and one of them anastomosed, in all of the spec-
Zoologica. Heft 67. IQ