BY WILLIAM A. HASWELL, M.A., B.SC. 115 



SCYLLID.E. 



The centra of the vertebrae present radiating lamellae. 



The articular surface for the hyo-mandibular is situated in great 

 part on a postero-lateral process of the skull ; it is saddle-shaped, 

 and not very deep. There is no ethmoidal canal. The rostrum is 

 three-barred. The dorsal fin has no broad basal cartilages. 



Rhinidjb. 



The centra of the vertebra? are devoid of radiating lamellae. 



The post-orbital process is produced forwards and unites with 

 the praeorbital process. The shoulder-girdle i-eseinbles that of the 

 Rays in presenting a rigid ventral portion ; and the skeleton of 

 the pectoral fin has the pro and meta-pterygia elongated in an 

 antero-posterior direction as in the Rays. The skeleton of the 

 dorsal fin presents wide basal cartilages apparently continuous 

 with the neural spines, and has no distinct rays. 



PRISTIOPHORIDiE. 



The centra of the vertebrae are devoid of radiating lamellae of 

 bone. 



The ethmoidal region of the skull is produced forwards into a 

 long, dorso-ventrally compressed rostrum, perforated by a longi- 

 tudinal canal, which is continuous behind with the cranial cavity. 

 The copula of the hyoid is reduced to the form of a narrow strip 

 of cartilage. There are rays on the hyo-mandibular as well as on 

 the hyoid arch. The propterygum is very small. The dorsal fins 

 are supported by broad thin plates continuous with the neural 

 arches of the vertebrae. 



BATOIDEI. 



The post-orbital processes are small or absent ; the orbit is 

 devoid of cartilaginous floor. There is no palato-basal articulation. 

 The rostrum, when present, is usually imperforate at the base. 

 There are no external branchial arches ; the first branchial arch 

 is sometimes directly connected with the skull. When the hyoid 

 arch is supported by the hyo-mandibular the articulation takes 



