427 



dibular and ceratohyal have been described by Gegenbaur^) and 

 Gadow ^), but those connecting the hyomandibular with the skull have 

 received less attention. The latter will be frequently referred to in the 

 following notes and so, pending further investigations, the provisional 

 names, superior post-spiracular ligament and inferior 

 post-spiracular ligament are here applied to the two ligaments 

 of S c y 1 1 i u m , described in the preceding paragraphs. 



rroci 



Fig. I. Scyllium cauicula. Dorso-lateral view of skull, showing the relations 

 of the post-spiracular ligaments, and the dorsal spiracular caecum. 



c overhanging cartilage of the auditory capsule ; dc dorsal spiracular csecum ; 

 Ü superior post-spiracular ligament ; hm, hyomandibular cartilage ; ch ceratohyal ; md mandible ; 

 sp external aperture of spiracle ; il inferior post-spiracular ligament ; pg palatoquadrate 

 cartilage. 



The pre-spiracular cartilage of Scyllium is a very thin plate 

 of cartilage, quadrangular or pentagonal in outline. It is not connected 

 with either of the post-spiracular ligaments, but is situated with its 

 posterior, slightly concave surface in relation with the pseudo-branchial 

 mucous membrane of the anterior wall of the spiracle, and with its 

 anterior surface very loosely attached to the muscle^) that runs 

 upwards from the palatoquadrate cartilage to the under surface of 

 the ledge that projects laterally from the supero-external surface of 

 the auditory capsule. 



Bd. 



2) Kopfskelet der Selachier, Leipzig 1872, 



3) Phil. Trans. 1888. 



4) "Levator maxillae superioris" of Vettek. 

 VIIL 



Jenaische Zeitschrift, 



28* 



