104 BULLETIN OF THE ESSEX INSTITUTE. 



By a fusion of the anterior ends of the trabecule in the 

 median lines a small ethmoid plate is formed, upon the 

 anterior end of which is a slight prominence, the only in- 

 dication we have of a nasal septum. Upon each side a 

 short forward-projecting process terminates the ethmoid 

 plate anteriorly. 



Entirely separated from the rest of the cartilaginous 

 parts of the head there is now a delicate nasal capsule 

 (Fig. 16, nc). It consists of a curved rod, which runs 

 along the dorso-median surface of the olfactory organ, fol- 

 lowing more or less closely the direction of the anterior 

 end of the trabecula and the ethmoid plate, and a number 

 of shorter processes projecting laterally from this main 

 rod over the top of the olfactory organ. As Piukus 

 ('94) has pointed out, there is some resemblance between 

 this nasal capsule and that of Protopterus, but it seems to 

 me hardly necessary, for reasons which will appear more 

 fully later, to attach any importance to this similarity other 

 than that of a coincidence. 



One would seem justified in expecting that, if Necturus 

 occupy a position intermediate between the Stegocephali 

 and the Urodela, the chondrocranium of Necturus would 

 show more or greater differences from the typical Urodele 

 chondrocranium than are found in higher Urodeles, the 

 Urodela of Cope. But I am unable to discover that this 

 is the case. It would be difficult, rather, to point out a 

 form in which the chondrocranium is more typically Uro- 

 delan. 



Amphiuma means. 



The first of the two models of the chondrocranium of 

 Amphiuma means here described is the one which formed 

 the basis of the description of the chondrocranium in Dr. 

 Kingsley's preliminary paper upon "The Head of an 

 Embryo Amphiuma" ('92). The chondrocranium of 



