138 EDWARD PHKLPS ALLIS, JUN. 



teleosts and ganoids lodges oi' transmit?, as the canal in 

 selachians was asserted to, a lymph vessel which arises as a 

 branch of a peri-orbital lymph sinus. This assumption I 

 found to be incorrect in so far as Amia is concerned (3), the 

 eye- muscle canal of that fish being traversed by a vein, and 

 not by a lymph sinus, and a separate and wholly distinct 

 transverse canal transmitting a lymph vessel from orbit to 

 orbit. I hence concluded that the eye-muscle canal of Amia 

 and teleosts was not derived from the canalis transversus of 

 selachians. This opinion must certainly now be altered, for 

 if the canal in selachians transmits a vessel that is primarily 

 venous, it is evident that it must form a part of the eye- 

 muscle canal of Amia, which canal also transmits a venous 

 vessel. 



One other foramen in the orbital region of Mustelus is to 

 be noted. It lies near the anterior end of the orbit, dorso- 

 posterior to the orbital opening of the orbito-nasal canal, and 

 anterior to all the foramina of the nerves, the nervus opticus 

 included. It is, in all probability, traversed by a branch of 

 the peri-orbital sinus, though I could not positively establish 

 this. A branch of the sinus penetrates the membranes that 

 line the outer surface of the cartilage, and is seen, for a 

 certain number of sections, as a vessel lying between the 

 outer and inner lining membranes of the skull. The two 

 edges of the foramen had then been pressed toward each 

 other by contraction or displacement in manipulation, and I 

 could not see that the vessel entered the cranial cavity. In 

 this latter cavity tAvo blood-vessels approached the mem- 

 brane that lined the inner surface of the opening in the 

 cartilage, and there united. These two vessels seemed to be 

 simply two parts of a single vessel that approached the fora- 

 men and then bent sharply away from it, without having any 

 connection whatever with the external vessel. If, however, 

 such a connection existed, the intra-cranial vessels would be 

 branches of the branch of the peri-orbital sinus, and the vessel 

 would probably be the anterior cerebral vein of Parker's 

 descriptions of the adult Mustelus antarcticus (47). 



