“ PROBOSCIS PORES ” IN CWANIATE VERTEBRATES. 547 
excessive prolongation forwards of the notochord in Amplii- 
oxus, they would both appear as ectodermal organs situated 
below the brain and in front of the mouth. If we restored 
the bilateral symmetry of the head in Ampliioxus, both the 
Text-fig. 3. 
Diagrams of transverse sections through the premandibular 
region of the head of a. Amphioxus (restored to a bilaterally 
symmetrical condition). b. Torpedo, and c. The Reptile 
G-ongylus (from the figures of Salvi). H. Hypophysis. S 1 . Pre- 
mandibular somite, or first anterior ccelomic sac. 
right and the left anterior coelomic sacs would open into this 
ciliated depression as shown in Text-fig. 3a ; and there would 
be two “ proboscis pores.” Now the suggestion I wish to 
