2698 THE LUNGFISHES AND CHIMsEROIDS 



greater part of the year, only resuming their normal aquatic life with the return of 

 the wet seasons. Professor W. N. Parker, who received some specimens in the 

 torpid condition, writes that about a hundred individuals were dug out and packed 

 up in crates still inclosed in the clods of mud. On arrival in Europe the clods 

 were opened, and the fishes placed in a tank in a hothouse. The statement of the 

 natives that the species grows to the almost incredible length of six feet suggests 

 that it must be a very long-lived creature. From the above-mentioned specimens 

 it was found that these mudfishes grow very rapidly, have great vitality, and, 

 although able to sustain fasts, are exceedingly voracious, devouring all the snails, 

 earthworms, and small fish given them, and then killing and eating each other, 

 making it difficult in the extreme to preserve the specimens. They are most 

 active at night, and appear to keep mostly to the shallow water, where they 

 move deliberately about on the bottom, alternately using the peculiar limbs of 

 either side, though their movements do not seem to be guided by any strict regu- 

 larity. Gray has compared these movements to those of a newt, and several 

 other observers have noticed them. The powerful tail forms a most efficient 

 organ for swimming rapidly through the water. It is well known that this fish 

 comes to the surface to breathe at short intervals, and thus it is evident that 

 the lungs perform an important, if not the chief, part in respiration during the 

 active life of the animal. The air passes out again through the opercular aper- 

 ture, and the movements of the operculum itself indicate the fact that bronchial 

 as well as pulmonary respiration takes place. Externally, the sexes present no 

 characteristics whatever distinguishing them apart. As in the American species, 

 -external gills are developed in the young. As regards the breeding habits of 

 these fishes nothing very definite is known. It is stated, however, that the numer- 

 ous eggs and embryos are carried about in an elongated gelatinous pouch attached 

 to the sides of the back of one of the parents, although the sex in which these 

 receptacles are developed does not appear to have been ascertained. In conclusion, 

 it may be observed that Professor Parker is of opinion that although the lung- 

 fishes present certain resemblances on the one hand to some of the sharks and 

 ganoids and on the other to the lower Amphibians, yet they appear so distinct 

 from both that he thinks they ought to be removed from the fishes to form a class 

 by themselves. 



In the Palaeozoic epoch lungfishes formed an abundant group, which 



ung " may be divided into three families. Of these the Carboniferous and 

 fishes 



Permian Ctenodontidtz , as represented by Ctenodus and Sagenodus, re- 

 semble the existing forms in the absence of marginal teeth to the jaw and of jugular 

 plates on the throat, but differ by the numerous membrane bones of the skull; the 

 caudal fin being of the fringed type, and the scales cycloidal. The type genus 

 which includes species of five feet in length, takes its name from the comb-like 

 structure of the ridged palatal teeth. The second family, Phaneropleurida , differs 

 from the last in the presence of both marginal teeth and jugular plates; the 

 typical genus Phaneropleurum, including small species from the Devonian. In the 

 Dipterida*, as represented by the Devonian Dipterus and Pala>daphus, jugular plates 

 are present, but there are no marginal teeth, and the tail is of the heterocercal 



