The Musculus mylohyoideus and M. interhyoideus in Necturus

Casual dissection of the ventral surface of the head in Necturus reveals an extensive area of muscle fibers crossing the throat and extending from the tip of the lower jaw to the gular fold. The connective tissues and fascia in this area partly mask the fibers; and the muscle fibers collectively have in several instances been described as constituting a single muscle, the M. mylohyoideus. In reality two separate muscles are involved, and each consists of two parts. Here follows a tabulation of the synonymy, and a brief description of the muscles

The Pelvic Musculature of Necturus

The musculature of the pelvis and hind-limb of salamanders as a group has received but little attention (Francis, 1934). The myology of Necturus has been studied even less than in certain other genera. It is true that many standard manuals of comparative anatomy list certain of the muscles of Necturus, but the descriptions made and names used in many cases are so variable as to be of little value. Mivart (1869) dissected one specimen of Necturus and sketchily presented his findings. Wilder (1908, esp. 1912, and 1923) did especially valuable work on the limb-muscles of Necturus; his descriptions will be referred to many times. Francis (1934) tabulated the various synonyms for and described each of the muscles of Salamandra. I have adopted his terminology for this report on the musculature of the pelvis of Necturus

Note on the Blood of Necturus

Since 1867, when van der Hoeven first recorded measurements of the red blood cells of Necturus, at least 60 papers have been published dealing in whole or in part with its blood. A few additional notes are included here

The Musculus Depressor Mandibulae in Necturus

A small amount of confusion appears in the literature on the cranial myology of Necturus, and the Urodela generally, by the use, among divers anatomists, of the same name for two different muscles. Both of these muscles function as depressors of the lower jaw. On occasion, both muscles have been named digastric, and depressor mandibulae ; and other names have also been used. In order to clarify the use of the terms M. depressor mandibulae and M. branchio-mandibularis, I have inserted tables of the synonymy for these two muscles in the Urodela, with brief descriptions of these muscles in Necturus

The Muscles of the Forearm of Necturus

Little of a completely satisfactory character has been published on the arm-myology of Necturus. Mivart (1869) dissected a single specimen, and described certain of the foreleg muscles. Ribbing (1906-07) dissected two specimens, and included some notes on the foreleg of Necturus, but most of his paper deals with Siredon and other forms. Wilder (1908, 1912) presented a good account of the muscles of the foreleg, and his descriptions will here be referred to many times. Howell (1936) and Straus (1942) discussed the anatomy of the flexor muscles of the forearm of Necturus; but they were interested in the broader problems of the homologies of flexor muscles. Francis (1934) tabulated the various synonyms used for the muscles of the forearm of Salamandra. His descriptions are so complete that I have used his terminology wherever it applies to the muscles of Necturus

The Natural History of Necturus: II

Necturus has permanent external gills, simple internal lungs, and a skin well supplied with blood vessels; all of which have been reported functional in respiration

The Natural History of Necturus, IV. Reproduction

Information on the life cycle of Necturus has accumulated slowly. Naturalists long were uncertain as to whether they had adult animals, since Mitchill\u27s (1822) mistaken idea that they get to be two feet long was widely current. Lacepede (1807) believed that mudpuppies might be larval, and their adults unknown; Say (1818) that the mud puppy was the larva of the hellbender. Barton (1807) confused the mudpuppy and the hellbender. Gray (1857) was ... inclined for the present to consider the Proteus of the Lakes as a distinct kind of Batrachian, which is arrested in its development, and never reaches the perfect state. Cope (1866) said, The relation then between Necturus and Spelerpes is probably the same as that between Siredon and Amblystoma... ; and Kollman (1885) that the relation between Necturus and Batrachosops was the same as that between Axolotl and Amblystoma. Cox (1907) believed that members of the Proteidae undergo metamorphosis, ... the young being more or less unlike the adults. Necturus was described as ... a form arrested in development . Netting (1933) called Necturus the Peter Pan of salamanders, for it never grows up

The Skeleton of the Arm of Necturus

Wilder\u27s (1903) description of the skeleton of Necturus is the only one, to date, that is anywhere near complete. Other authors (Mivart, 1869; Ribbing, 1906-07; Howell, 1936; Straus, 1942) have noted portions of the arm-skeleton incidentally to describing various muscles. Chen (1935) described the embryonic development of the pectoral limb. All of these notes generally agree, except in a few details. Francis (1934) described the skeleton of Salamandra. For reasons to appear later, I adopt the terminology of Francis for the skeletal elements of the arm of Necturus

The Levator anguli scapulae in Necturus

Professor St.-George Jackson Mivart first described the M. levator anguli scapulae in N ecturus in 1869. He noted an origin of the long, slender muscle on the occiput, and an insertion on the inner side of the dorsum of the scapula.\u27\u27 Mivart, earlier in the same year, had used the same name· for a homologous muscle in the hell-bender; in this, he apparently adapted Funk\u27s (1827) and Rtidinger\u27s (1868) earlier name. Kingsley (1907) used the name M. levator scapulae for the same muscle, following an earlier pattern set by Carus (1828), Schmidt, Goddard, & van der Hoeven (1864), Humphry (1871) and Osawa (1902)