178 William Sörensen 
derably larger and more marked on the concave than on the con- 
vex face. 
Fig. 4. Fig. 5. 
Cm" AR 
Figg. 3, 4, and 5 (Copies of Figg. 20, 21, and 22 in my book). Doras maculatus Cuv. et Val. The first 
ray of the right pectoral fin, natural size; in Fig. 3 seen from the base and a little obliquely from 
above; in Fig. 4 seen obliquely from the base, from behind, and from below; in Fig. 5 seen in 
front, somewhat obliquely. — R, the foremost denticulated edge of the ray; y, 4, the vertical part 
of the diarthrosis; «, ß, the two remaining parts of the diarthrosis, each on its process; J, d, the 
process acting as a brake (the »Kegel« or »Gelenkkopf« of Dr. Turmo, after whose interpretation the 
process, bearing the part 6 of the diarthrosis, is a »Hemmfortsatz«); ** the scouring faces of the 
process 0, — z, the process carrying sp. 
The muscles!: ea, the place of insertion of two muscles, which 
I call M. exterior anterior and M. interior anterior; they carry the 
Spine forwards, if (by torsion) it is placed in the position brought 
about by the operation of the muscle inserted on sp, but are unable 
to do so, if (by torsion) the spine is placed in the position brought 
about by the operation of the muscle inserted on ep. — ip, the 
place of insertion of a big muscle, M. interior posterior, carrying back- 
wards the ray, if the ray is placed in the position brought about 
by the operation of the muscle inserted on ep, but is unable to do 
so, if the spine is placed in the position brought about by the 
operation of the muscle inserted on sp. — ep, the place of insertion 
of a small muscle, M. exterior posterior, which — in Doras and 
Synodontis, for in this memoir I do not mention the effect of the 
muscles in the other genera — twists the ray so that its hindmost 
denticulated edge is turned a little downwards, that the process 6 
is twisted backwards and upwards, so that its interior face in front 
and its exterior face behind are brought into contact with the walls 
of the groove of »Humerus«, which are all through furnished with 
naked smoothly polished faces, and that in front the process 0 
' See the Figg. 26, 27, and 28 in my book. 
