No. 2.] AMPHIUMA MEANS. 385 



muscle is transformed into two tendons which, passing along 

 the parietal groove, descend anterior to the prootic, and are 

 inserted together in the coronoid process. The arrangement 

 of this muscle is such as to give great strength and yet pre- 

 serve the flat attenuate condition of the head in the prootic 

 region. The cervico-parietalis muscle arises from the second 

 and first vertebrae, and is attached to the posterior part of the 

 parietal and the dorsal area of the exoccipital bone. The 

 lateral head-region presents five muscles : cucularis, digas- 

 tricus-maxillae, interbranchiales constrictores arcuum bran- 

 chiarum, levatores arcuum, and adductores arcuum. The 

 cucularis arises from the fascia of the transverse processes 

 and descends a narrow band of muscle anterior to the fore- 

 limb to its insertion in the walls of the oesophagus. The 

 digastricus maxillae is a large flat muscle arising in three por- 

 tions. The first portion is attached to the neural spines in 

 the shoulder region and is a continuation of the superior dor- 

 sal muscle. The second portion arises from the summit of 

 the first epibranchial and mingles inseparably with the first. 

 The third portion is the strongest, and arises from the pos- 

 terior otic region, joining the other two immediately, whence 

 the entire mass passes downwards and forwards to a firm 

 insertion in the posterior angle of the lower jaw. Bronn's 

 Their-Reichs (10) describes only two portions as origins of this 

 muscle. The writer has detected several errors in this work 

 in the descriptions of the muscles of the head of Amphiunia. 

 The interbranchialis constrictores arcuum branchiarum exist 

 as thin oblique bands of muscular fibre between the first, 

 second, and third epibranchials, but no fibre joins the third 

 and fourth, between which the gill slit persists in the adult. 

 The levatores arcuum arises from the inferior side of the 

 posterior portion of the digastricus and descends as a flat 

 band of fibres to its insertion on the summits of the epibran- 

 chials. The adductores arcuum consist of a tendinous band 

 connecting the summits of the four epibranchials, whence it 

 extends downwards and backwards to a point above the fore- 

 limb, where its course becomes transverse, forming the third 

 inscriptio tendinea. The ventral head-region presents eight 



