ZOOLOGY. 



797 



other members of their class as to be without them. Nevertheless, it is 

 evident that the branchiaB soon become functionless, so that the animal 

 is almost, if not exclusively, an air breather, and that functional activity 

 is not resumed till a more advancx'd age." Indeed, from observations 

 of a specimen in an aquarium, which for a time had no branchia? at all, 

 it appeared that " sirens may be exclusively air breathers." Professor 

 Cope urges that in explanation of this fact, it may be remarked that 

 this atrox)hy cannot be accounted for on the supposition that it is sea- 

 sonal and due to the drying up of the aquatic habitat of the sirens. The 

 countries they inhabit are humid, receiving the heaviest rainfall of our 

 Eastern States, and there is no dry season. The only explanation ap- 

 pears [to him] to be that the present sirens are desceuilants of a terres- 

 trial type of batrachia which i)assed through a metamorphosis like other 

 members of their class, but that more recently they have adopted a per- 

 manent aquatic life, and have resumed their branchiae by reversion." 

 {Am. Nat, v. 20, i)p. 1S2G, 1227.) 



Peculiarities of Ccecilians. — The life history of the singular worm-like 

 Amphitrans, representing the order Gymuophiona and the family Caj- 

 cibiidse, is still imperfectly known. Some characteristics have been de- 

 scribed recently by the brothers P. B. and C. F. Sarason. In an advanced 

 stage, shortly before hatching, the embryo is provided with very long 

 blood red external gill filaments, an<l has also a distinct tail, with a strong 

 tin. The gill filaments are shed previous to hatching, after which the 

 young Gaecilians make their way to a neighboring stream, in which they 

 breathe by means of gill slits. After they leave the water their gill slits 

 close up, and they breathe by lungs. There is a fourth gill arch from 

 which the pulmonary artery is given off. The spermatazoon has a spiral 

 filament. The last two facts tend to show that the Caecilians were nearer 

 to the Modela than to the Anura, as is indeed amply shown to be the 

 (!ase by structural characteristics generally. It seems that there is a. 

 difference in reproduction manifested in closely related genera, for some 

 species are oviparous while others are viviparous. 



Reptiles. 



The classification oftlie Lizards. — A very important and much needed 

 work has been in progress of publication durin*g the past year in the 

 arrangement and description of the species of living lizards. Two vol- 

 umes oftlie projected three of the "Catalogue of Lizards iti the British 

 Museum" have already appeared, in which all the species known are de- 

 scribed and a number illustrated. The species have been thoroughly 

 revised from a systematic standpoint and grouped into natural genera 

 and families. The classification is mostly based ui)on such characters as 

 were made use of by Professor Cope about twenty years ago, but which 

 have not received due consideration from later writers. Professor 



