M. pseudotemporalis superficialis: M. spheno-maxillaris, Gadow, 1891:323—part of M. temporal, Shufeldt, 1890:16—part of M. pseudotemporalis, Hofer, 1950:468-477—part of M. adductor mandibulae medius, Edgeworth, 1935:277.
M. adductor mandibulae posterior: ? part of M. temporal, Shufeldt, 1890:16—part of M. adductor mandibulae medius, Edgeworth, 1935:58-59—? part of M. pterygoideus posterior, Adams, 1919:101, pl. 8, figs. 2 and 3.
M. protractor quadrati: part 4a of M. temporalis, Gadow, 1891:322-323, table 27, fig. 4—part of M. entotympanicus, Shufeldt, 1890:19-20, figs. 3 and 11—part of M. spheno-pterygo-quadratus, Edgeworth, 1935:57.
The terminology adopted by me is that of Lakjar (1926) except that the divisions of M. depressor mandibulae are designated by the Latinized equivalents of the names used by Rooth (1953:261-262).
M. pterygoideus ventralis lateralis.—The origin is fleshy and by aponeurosis on the ventral side of the palatine anterior to the palatine fossa. The insertion is fleshy on the ventromedial surface of the lower mandible and continues along the anteromedial surface of the internal angular process to its distal tip. A few fibers leave pars lateralis and insert on an aponeurosis which receives also all the fibers of M. pterygoideus dorsalis lateralis. The latter fact may have prompted Rooth (1953:257) to make the statement that the fibers originating on the dorsal part of the palatine inserted more laterally than those originating on the ventral side. Rooth worked with Columba palumbus, the Woodpigeon, and his description concerned M. adductor mandibulae internus pterygoideus, which is composed of Mm. pterygoideus ventralis et dorsalis of Lakjar (1926). His assertion that ventral fibers, that is to say, fibers arising on the ventral surface of the palatine, insert medially does not appear to be completely true for doves.
Aponeuroses cover most of the lower surface of the muscle and one or two nerves extend into the substance of the muscle. The nerves run from the anterior edge of M. pterygoideus dorsalis medialis and farther posteriorly from a separation in the muscle.
M. pterygoideus ventralis medialis.—The origin is by aponeurosis from the ventral surface of the palatine and fleshy from the palatine fossa. The aponeurosis is the same that gives origin to the fibers of pars lateralis. Part of the aponeurosis becomes tendonlike in the middle of M. pterygoideus ventralis and separates its two divisions. The insertion is fleshy on the lower one-third of the anterior surface of the internal angular process of the lower mandible, and by two tendons on the distal tip of that process. Many of the fibers of pars medialis insert on the tendons. The fibers at their insertion are not distinctly separate from those of pars lateralis and there is considerable mingling of the fibers. Consequently, the medial part of M. pterygoideus ventralis cannot be removed as a part distinct from the lateral part (figs. [1], [4], [10], [21] and [22]).
Ordinarily M. pterygoideus ventralis does not cross the ventral edge of the lower mandible, but in one white-wing the muscle was slightly expanded on the right side and it could be seen in lateral view. The homologous muscle in Columba palumbus apparently is consistently visible in lateral view. (See Rooth, 1953, fig. 6.)
M. pterygoideus dorsalis medialis.—The origin is fleshy on the dorsolateral surface of the palatine immediately anterior to the pterygoid and also on the anterior, dorsolateral, posterior and ventromedial surfaces of the pterygoid. The insertion is fleshy on the ventromedial surface of the lower mandible and the anterior surface of the internal angular process immediately dorsal to the insertion of M. pterygoideus ventralis lateralis.
M. pterygoideus dorsalis lateralis.—The origin is fleshy from the dorsolateral surface of the palatine, anterior to the origin of pars medialis and the insertion is by means of an aponeurosis on the medial surface of the lower mandible, lateral to the insertion of M. pterygoideus ventralis lateralis. The aponeurosis crosses the medial side of the insertion of M. pterygoideus dorsalis medialis. The fibers run in a posteroventrolateral direction and insert on the ventromedial side of the aponeurosis (figs. [1], [6], [8], [9], [13]-[22]).