492 



a short canal, or foramen, opens from the orbit and transmits the 

 efferent pseuclobranchial (mandibular) artery, this foramen not 

 being shown or described by Gegenbaur. The vessel that tra- 

 verses the canalis transversus is to all appearance a venous vessel, 

 but its connection with the venous system could not be established 

 because of the condition of both my specimens when attention was 

 first directed to this particular. Comparison with Mustelus (Allis, 

 1901), however, leaves little doubt of its being a venous vessel, the 

 conditions all being strictly similar in the two fishes. The small 

 median canal leading from the canalis transversus into the cranial 

 cavity must then transmit a median vein that drains the saccus 

 vasculosus and the pituitary region. 



Palais de Carnoles, Menton. May 1st, 1912. 



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