110 KDWAUD PHELPS ALUS, JUN. 



The superficial ophthalmic group is a long one, lying in 

 the upper part of the snout, and not far from the middle line 

 of the head. The ampullas of the group all lie mesial to the 

 dorso-lateral rostral bar of cartilage, the posterior ones lyiug 

 directly superficial to the nasal capsule. The ampullas are 

 grouped by their tubules in three somewhat separate sub- 

 groups. The tubules leading from the anterior sub-group 

 are relatively short, and radiate forward, laterally and 

 postero-laterally, their external openings all lying on the top 

 of the snout, the anterior ones mesial to the anterior portion 

 of the rostral part of the supra-orbital lateral canal, and the 

 posterior ones lying mesial to the large rostral group of 

 supra-orbital tubules and pores. In the specimen from 

 which the drawings were made there were forty- three 

 ampullas in this sub-group on one side of the head, and 

 forty-nine on the other, the number of ampullte being 

 determined by the number of related surface pores, which 

 alone were counted. 



The tubules leading from the second sub-group of super- 

 ficial ophthalmic ampullae are long, and run at first almost 

 directly laterally, forming a broad band, which lies at first 

 immediately posterior to the rostral group of tubules and 

 pores of the supra-orbital canal. The ampullary tubules 

 then turn backward and laterally, and pass superficially 

 across the supra-orbital canal immediately anterior to the 

 point where that canal bends backward in front of the eye. 

 The ampullary tubules here lie internal to the short mesio- 

 anteriorly directed section of the supra-orbital canal, and 

 internal to the tubules that arise from that section of canal, 

 the appearance being that of a band of ampullary tubules 

 that had here first pressed the supra-orbital canal inward 

 out of its normal relations to the external surface of the 

 head, and then pulled it out of a straight course and given it 

 the antorbital bend which seems otherwise not easily 

 accounted for. The external openings of these ampullary 

 tubules form a group of pores the anterior ones of which lie 

 mesial or directly superficial to the supra-orbital canal, while 



