Mar., 1903,] Spelerpes longicaudus. 3S9 



EXPLANATION OF PLATES. 



Kky to Plate 8. 

 A reconstruction of the skeletal elements of the head. 



SIDE VIEW. 



Parachordal cartilages. 

 Posterior foramen. 

 Coronoid process. 

 Auditory capsule. 

 Eirst Ijranchial arch. 

 Second branchial arch. 

 Third branchial arch. 

 Fourth branchial arch. 



Key to Plate 9. 

 A reconstruction of the skeletal elements of the head. 



VIEW OF THE BRANCHIAL APPARATUS. 



bh. Basilival cartilage. ba. First epibranchial cartilage, 



idi. Trohyal cartilage. bb. Second epibranchial cartilage, 



bra. First ceratobranchial cartilage. be. Third epibranchial cartilage, 



brb. Second " " bd. Fourth epibranchial cartilage, 



brc. Third " " ch. Ceratohyal cartilage. 



Key to Pirate 10. 

 A reconstruction of the skeletal elements of the head. 



VIEWED FROM AliOVE. 



tr. Trabeculae. pc. Parachordal cartilages. 



l)p. Basal plate of the trabeculae. au. Auditory capsule, 



la. Upper lal)ials. ch. Notochord. 



nb. Nasal pi^ocess. 



Key to Plate ir. 

 Reconstruction of muscles. 

 Figure /. — Lateral view 

 MtuL M. temporalis. Mra. M. rectus abdominis. 



Mia. M. levator arcuum l)ranchi- Mcb. M. cerato-branchialis. 



alium. I\Idm. M. depressor maxillae infer- 



Mld. M. longissinms dorsi. ioris. 



Mli. M. longissinms dorsi, inferior Mm. M. masseter. 

 fasciculus. 



Figure 2. — Ventral view. 

 Msm. M. submentalis. Mdb. M. depressor arcuum branch- 



Msb. M. submaxillaris. ialium. 



Mcb. :M. cerato-brenchialis. Mgh. M. genio-hyoideus. 



Msh. M. sternohyoideus. 



Figure j. 

 Reconstruction of branchial musculature. 

 Msm. M. submentalis. Msh. M. sternohyoideus. 



Mgh. M. geniohvoidetts. Mca. M. constrictor arcuum bran- 



]Msb. :\I. suljinaxillaris. chiahum, first fasciculus. 



I\Icb. M. cerato-branchialis. Mce. M. constrictor arcuum bran- 



Mhb. I\L hypobranchialis. chialium. 2nd fasciculus. 



Mab. M. depressor arcuum branch- Mci. M. constrictor arcuum bran- 

 ialitim. chialium, third fasciculus. 



In the reconstruction, the ceratobranchial muscles are removed, the sternohyoideus 

 muscles are cut out so as to show the M. depressor arc-lirauchialium, and one of the 

 geniohj'oideus muscles has been cut to show the origin of IM. sternohyoideus. The sub- 

 maxillaris has been represented as slit, and the flaps turned back. 



