342 Robert J. Terry. 



Paraphysis. Velar epithelium extends forward toward thepara- 

 physeal region where there is to be seen a slight transverse fold 

 of the brain-roof. This fold, which appears to be the remains of 

 the paraphysis, forms the anterior end of a median longitudinal 

 groove of the tela, evident in transverse sections. The groove 

 is the beginning of a deep median invagination which in the adult 

 toad-fish separates two diverticula of the caudal end of the telen- 

 cephalic ventricle. 



Adult Opsanus 



Epiphysis. The fully developed epiphysis presents a form not 



uncommon among the teleosts (fig. 17). It consists of an oval 



end-vesicle terminating a long slender stalk, the whole structure 



being directed cephalad in the median plane and suspended in 



the meninges between the fore-brain tela and the cranial roof. 



The stalk, which is slightly fusiform, measures 6 mm. in length 



and 0.08 mm. in its greatest diameter. The end-vesicle measures 



0.6 mm. in length and 0.38 mm. in greatest breadth. There is no 



angle between the stalk and vesicle but a gentle curve extends 



throughout the length of the organ. The cavity, present in both 



stalk and vesicle, does not communicate with the ventricle. It is 



traversed by protoplasmic processes forming a wide mesh-work 



from wall to wall. An artery and vein are associated with the 



epiphysis throughout its whole extent. In the connective tissue 



along these vessels and around the distal half of. the organ black 



pigment is present in considerable amount. The commissural 



canal of the lateral line system is now far anterior to the end of 



the epiphysis and there seems to be no further relation between 



these organs. A parietal foramen or fossa of the osseous cranial 



roof is not present. 



Superior Commissure. There is no change in the structure 

 and relations of this commissure from what was last observed. 



Posterior Commissure. The two divisions of the posterior 

 commissure are still recognizable; the intervening connective tissue 

 septum now is less distinct. The anterior division contains some 

 longitudinal fibers which extend in a thin layer around the base 

 of the epiphyseal stalk and on to the intermediate tubercles. 



