THE STATE GEOLOGIST. 51 



The habits of existing Lung-fishes are interesting. Neocera- 

 todus lives all the year round in the water, there being no evidence 

 that it ever becomes dried up in the mud, or passes into* a summer 

 sleep in a cocoon; and its paired fins, moreover, are useless for 

 progression on the land. The following account of the habits of 

 the remaining genera is taken from the "Cambridge Natural His- 

 tory" : 



"Protopterus has a wide distribution over the middle portion of the great 

 African continent, * * * and is usually found in marshes in the vicinity of 

 rivers. The tail is the principal organ of locomotion, and by its means the fish 

 is capable of remarkably quick, agile movements. When slowly moving over 

 the bottom of an aquarium the paired limbs are observed to move to and fro 

 on opposite sides alternately in somewhat bipedal fashion. The limbs are use- 

 less for swimming, although it is possible that they may be helpful in creeping 

 over the bottom, or in balancing, or as tactile organs. Protopterus is said to 

 breathe by its lungs as well as by its gills, and to rise to the surface at short 

 intervals to take in fresh air. In the dry seasons the marshes in which Pro- 

 topterus lives become dried up, and to meet this adverse change in its sur- 

 roundings the fish activates, or passes into a summer sleep, until the next 

 rainy season brings about conditions more favorable to active life. Prepara- 

 tory to this summer sleep, and before the ground becomes too hard, the fish 

 makes its way into the mud to a depth of about 18 inches, and there coils itself 

 up in a flask-like enlargement at the bottom of the burrow. * * * While 

 encapsuled in its cocoon the fish is surrounded by a soft, slimy mucus, no 

 doubt for the purpose of keeping the skin moist, and its lungs are the sole 

 breathing organs, the air passing from the open mouth of the burrow through 

 the hole in the lid directly to the mouth of the animal. * * * The length 

 of the summer sleep naturally varies with the duration of the dry season, and 

 probably it lasts on the average nearly half the year (August to December). 

 The cocoons, embedded in an outward casing of hardened mud, have often 

 been brought to Europe, and when placed in water of suitable temperature the 

 long torpid Protopterus escapes from its prison in a perfectly healthy condi- 

 tion and resumes its partly branchial and partly pulmonary mode of breath- 

 ing. 



"Lepidosiren paradoxa, probably the only species of the genus, is confined to 

 South America. * * * Of sluggish habits, the fish wriggles slowly about 

 at the bottom of the swamp like an eel, using its hind limbs in an irregular 

 bipedal fashion as it wends its way through the dense network of subaqueous 

 plants. * * * Like other living Dipneusti, Lepidosiren rises to the surface 

 to breathe. The intervals are, however, very variable, and no doubt depend 

 on the relative purity or impurity of the water. Both expiration and inspira- 

 tion are said to take place through the mouth. The snout is protruded on the 

 surface and the creature expires. After being withdrawn for a moment the 

 head is again projected and inspiration takes place through the partially 

 opened lips. When the fish finally sinks a few bubbles of surplus air escape 

 through the gill-clefts. * * * Like its African relative, the fish ceases to 

 feed on the approach of the dry season and eventually hibernates at the dilated 

 extremity of a tubular burrow, the entrance to which is plugged by a small 



