56 THE VOYAGE OF H.M.S. CHALLENGER. 



Muscle No. \. (ventre exteme), Meckel, vol. vi. p. 4, No. L 

 Sacro-lumhalis, Owen, p. 25. 

 Sacro-lumhalis, Selenka, vol. vi. p. 93, No. 1. 

 Sacro-lombaire, Gervais and Alix, p. 13. 



Attachments. — This muscle consists of a flattened band, which measures one inch in 

 hreadth at its origin. It arises from the anterior as well as from the outer margin of the 

 iliac bone, and passing forwards is attached to each of the vertel)ral ribs external to their 

 tubercles. The muscle terminates by being inserted into the transverse process of the 

 first dorsal vertebra. 



Action. — This muscle extends the cer\T[cal upon the dorsal portion of the vertebral 

 column. 



Relations. — It rests upon the ribs, and lies to the outer side of the longissimus dorsi. 



Nerve supply. — Branches from the posterior divisions of the dorsal nerves. 



Remarks. — Meckel directs attention to the large size of this muscle in the Penguins, 

 and associates it with the erect position habitual to these birds when on land. Gervais 

 and Alix describe the muscle as consisting of three distinct portions in Eudyptes 

 chrysolophus. These I faded to recognise. 



2. Longissimus dorsi. 



Costo-cervical (part of), Vicq d'Azyr, ITVi, p. 580, No. 2. 

 Der innere Ruckgrals-Streclicr, Tieilemann, p. 289, No. 6. 

 Miisde No. 1 (ventre interne), jMeckel, vol. vi. jj. 4. 

 LongisdmiLs dorsi, Owen, p. 2G. 

 Longissimus dorsi, Selenka, vol. vi. p. 94, No. 2. 

 Long du dos, Gervais and Alix, p. 1 3. 



Attachments.— The. longissimus dorsi occupies the groove between the spinous and 

 transverse processes of the dorsal vertebrae. It consists of a number of short fibres, 

 which arise from the anterior margin of the ilium, and from the spinous and transverse 

 processes of the dorsal vertebrae. The fibres pass forwards, and are inserted into the 

 neural arches of all the dorsal vertebrae. At the root of the neck they are to some 

 extent continuous with the fibres of the extensor colli magnus. 



Action. — This muscle extends the cervical upon the dorsal portion of the vertebral 

 column. 



Relations. — The longissimus dorsi fills up the dorsal vertebral groove. It is con- 

 cealed superficially by the biventer cervicis which rests upon it. 



Nerve supply. — Numerous branches from the posterior divisions of the dorsal 

 nerves. 



