57 6 



PISCES FISHES. 



animal may remain dormant for many months, e.g. from August to 

 December. The air seems to pass directly from the mouth of the 

 burrow, through the aperture of the capsule-lid (which is produced 



sn.t. 



e.br 



PC. I. 



FIG. 309. Head region of Protopterus. From W. N. Parker. 



sn.t. i Sensory tubes ; /./., lateral line ; e.br. y external gills ; pc,l. t 

 pectoral fin ; op., operculum. 



inwards in a short pipe) to the nostrils, and thence to the lungs. 

 The nourishment appears to be derived from a store of fat deposited 

 in the lymphoid tissue around the reproductive organs and kidney^ 

 and among the lateral muscles of the tail (cf. fatty bodies in 



FIG. 310. Larva of Protopterus. After Budgett. 

 e.g.) external gills ; PC., pectoral fin ; Pv., pelvic fin. 



caterpillars, amphibians, etc.). Moreover, some of the muscles are 

 replaced by fat, and others undergo a pathological granular degenera- 

 tion (cf. lamprey). To a certain extent, therefore, the dormant 

 animal lives on its own tail. It is probable that leucocytes aid in the 

 absorption and transportation of the degenerated muscles (cf. tadpoles). 



