EXPLANATION OF THE EEFERENCE LETTERS USED m 



THE PLATES. 



[Note. — In many instances in Dr. Sagemehl's article the letters in his text do not 

 agree with the reference letters of the figures in his plate ; then, again, Franque used 

 a different system of letters, as did the writer. This gave much trouble ; hut it is 

 hoped that in the explanation of these letters, here given, the references will all be 

 made clear, both for the text and the figures. — K. W. S.] 

 a. Admaxillary ; frontal (Fig. 7, Plate II) ; also one of the ossifications of Meckel's 



cartilage (see Plate V, Figs. 17 and 18), and a a ligament between nasal and 



frontal. [Franque.] 

 ag. Angular. [Bridge.] (See Plate V, Figs. 17 and 18.) Also Ang. (Plate III and 



others. ) 

 An. Preorbital (Plate IV, Fig. 16) ; antorbital. 

 an. Angular (Plate VII). 



Art. Articular (P^, os coudyloideum of Franque, Plate X). 

 As. Alisphenoid. 

 Ast. Actinosts. 



/3. Ossa in eutem immissa (Franque), supratemporal of the author 

 h. Parietal of Franque (Fig. 7). 



1). One of the ossifications of Meckel's cartilage (Plate V, Fig. 17). 

 i. a. Branchial arches. 

 B. 0. Basioccipital. 

 JBi's. B. Branchiostegal rays. 



B. S. Basisphenoid. 

 Bs. h. Basibranchials. 



c. One of the ossifications of Meckel's cartilage in Plate V. 



c. Os mastoideum (Franque), the squamosal of the other figures; Sq. 



ea. Carotid foramen. 



cb. Vascular canal of the occiput (in basioccipital). 



ce. External semicircular canal. 



C. hy. Cerato-hyal. 



cp. Posterior semicircular canal. 



or. Coronary cartilage (Bridge), Plate V, Fig. 17. 



Cs. Anterior semicircular canal. 



c. V. Neural arch of first vertebra in Albula and the co-ossified first vertebra in Jfc^o- 



lops. 



D. Dentary. 



d. One of the ossifications in Meckel's cartilage. (Bridge.) Plate V. 



d. NasaL (Franque.) PI. II, Fig. 7. 



d'. Os alare (Franque) ; the author's antiorbital, while Franque's antorbital A I have 



the lacrymal. 

 S'. Posterior nasal aperture. (Franque. ) 



e. Ethmoid of Franque. (PI. II, Pig. 7.) 

 Ecpt. Ectopterygoid. 



E. hy. Epihyal. 



92 • 838 



