292 MR. R. H. BURNE ON THE [Apr. 1 8, 



The libs and the nuchal plate are embedded in the deep sui'face 

 of the dense integumentary cai-apace. In a similar way, the 

 dorsal parts of the dorso-lumbar region of the vertebral column 

 are partially embedded in the deeper parts of the carapace as far 

 back as the last ribs. The sacrum and tail are free. The sacral 

 region had been injured by a spear-thrust and the surrounding- 

 parts were somewhat decayed, so possibly the freedom of the 

 sacrum may have been artificial. 



The Muscular System. 



The muscles of the trunk of a young animal have been 

 described by Rathke*. and those of the shoulder in another small 

 specimen by Furbringer t. As most authors, who have dealt with 

 the muscles of Reptiles, have used dififerent names for the same 

 muscle, I have thought it best to adopt the names and numbers 

 given by Hoffmann in Bronn's ' Thierreich ' (Bd. vi. Abt. iii.) — in 

 the first place because they do not carry witii them any implied 

 homology with the muscles of mammals, and in the second place 

 because a full synonymy is given with each name and the com- 

 parison with other descriptions is thereby very much simplified. 

 An exception has been made in the case of the hind-limb muscles, 

 for which Dr. Gadow's + names and numbers are used. 



Muscles of the Head and Keck. 



Sqimmoso-maxillaris (dep7^essor maxillce) (text-fig. 55. 11).— 

 Origin: hinder edge of the squamosal. Insertion: ventral surface 

 of the angle of the jaw. 



A cylindrical muscle with fieshy origin and insertion. Separated 

 at its origin into two pai'ts by the insertion of a slip of the 

 mylohyoid. 



Dilator tuhce (text-fig. 55. 12). — Origin : squamosal, internal to 

 origin of squamoso-maxillaris. Insertion : upon the external 

 meatus. 



Testo-occvjntis (text-^g.^^. 13). — Origin: the anterior part of 

 the nuchal plate, close to the mid-line. Insertion : the hinder 

 edge of the parietal, 2 cm. from the mid-line. 



A cylindrical muscle 2 cm. in diameter. 



TestO'Capitis (text-fig. 55. 14). — Origin: the carapace, along a 

 line that slopes outwards from the point of the fiist rib to the 

 second. Insertion : the hinder margin of the skull between the 

 insertion of the testo-occipitis and the origin of the squamoso- 

 maxillaris. 



A very powerful muscle, with an extensive narrow origin. 



Cervico-capitis (text-fig. 55. 15). — Origin: the dorsal parts of 



* Eathke : Ueber die Entwickkmg der Scliildkroteu, 1848, p. 154. 



f Furbringer : " Zur vergl. Aiiat. der Schultermuskeln," Jena. Zeits. Bd. viii. 

 1874, p. 221. 



J Gadow : " Beitr. zur Mj-ologie d. liinteren Extremitiit der Reptilien," Morpli. 

 Jabrb. Bd. vii. 1882, p. 329, 



