No. 2.] AMPHIUMA MEANS. 377 



slate gray ventrally. The head is covered with mucous pores, 

 arranged in several rows which unite in the region of the neck 

 so that only two distinct rows are seen on each lateral area of 

 the body. Cope (4) errs in saying none are present on the 

 body. 



Bones of the Head. 



The head of Amphiuma is long and narrow, the general out- 

 line being somewhat like that of the skull of the Proteus except 

 that the snout is not so pointed. While in the majority of 

 Amphibia the skull is as broad as long, in Amphiuma it is 

 twice as long as it is broad. It is composed of twenty-eight 

 distinct bones : two maxillaries, a premaxillary, two nasals, 

 two frontals, two prefontals, two orbitosphenoids, two vomero- 

 palatines, two parietals, two exoccipitals, two prootics, two 

 pterygoids, a parasphenoid, two stapes, two quadrates, and two 

 squamosals. The maxillary is an irregular, oblong bone with a 

 triangular cavity beneath, along one side of which are attached 

 twenty-two conical teeth. This bone is not curved as in the 

 majority of amphibians, but presents a straight alveolar edge. 

 The foramina (Fig. i, c, b) are seen on its dorsal surface, the 

 anterior of which gives passage to small blood vessels and 

 nerves. Cope (4) believes that the larger foramen is prophetic 

 of the tentacular canal of the Gymnophiona. The maxillary 

 articulates dorso-laterally with the prefrontal and nasal, ventro- 

 internally with the vomero-palatine, and anteriorly with the 

 premaxillary, which in Amphiuma is a single bone. This very 

 irregular bone is composed of three parts : the alveolar portion 

 (Fig. II, P) bearing ten teeth, the dorsal wedge extending 

 backwards between the nasals and frontals to a line joining 

 the orbits, and a ventral wedge lying in the roof of the mouth 

 between the vomero-palatines and parasphenoids. The greatest 

 width of either of these wedges is one millimetre, and the length 

 of each is about one third that of the skull. The nasals are 

 small bones very much pitted, and serve to roof in the anterior 

 part of the nasal chamber. The frontals are the longest bones 

 of the skull, and bound the fore brain both dorsally and an- 

 teriorly. They extend underneath the posterior edge of the 



