The Zoologist— March, 1869. 1577 



lustre. A series of mucus-pores begins near the inner margin of each 

 of the external nostrils, and diverging slightly extends over the nasal 

 and frontal regions. Opposite the eyes they each connect with an 

 orbital series. Another series, less distinct, exists on either side of 

 the throat, just below the ramus of the lower jaw. Of the four 

 branchial arches, only the three anterior support external processes, 

 and the latter are thickly studded on their lower surfaces with lamellar 

 fimbriae. The maxillary and palatine series of teeth have already been 

 mentioned. The former consists of a single row of slender pointed 

 teeth on the premaxillary and maxillary bones. The palatine arch of 

 teeth, situated on the vomerine and pterygoid bones, forms a narrow 

 and more complex series. The teeth of the lower jaw consist of 

 a single row on the premandibular bones, and an adjoining and 

 somewhat more complex series on the splenial bone. The two 

 close in between the maxillary and palatine arches when the mouth 

 is shut. 



The following measurements are taken from two of the Lake Coino 

 siredons. No. I is the individual figured at p. 1569, and No. 2 a 

 specimen preserved a short time in alcohol. 



Measurements. 



Length from SDuut to end of tail - - - 



„ gular fold - - - 



„ armpit - - - 

 „ groin 

 „ behind anus 



Width of head where greatest - - - 



„ tongue . - - . - 



Distance between eyes anteriorly - - - 



„ outer nostrils - - - 



„ inner ,, . - . 

 Length of anterior branchial process 



„ posterior „ - - 

 Distance between outstretched toes 

 Height of tail, including membranes where greatest 



Before the transformation was entirely completed, the generic 

 characters of Amblystoraa had become unmistakable; although in 

 each^ instance — as not unfrequently occurs in nature — some of the 

 characters which distinguish the species had already preceded them. 

 Among the altered forms, developed from larva; apparently identical, 



SECOND SERIES — VOL. IV. N 



