B. VTII.] THE HISTORY OF AKIMALS. 313 



lower down rather than at Byzantium. This is the nature 

 of their migrations. 



CHAPTER XVI. 



1. LAND animals have also the same disposition for con- 

 cealment. For in winter they all hasten to conceal them- 

 selves, and appear again when the season becomes warmer. 

 Animals conceal themselves to guard against the excesses 

 of temperature. In some the whole race is concealed ; in 

 others only a part of them. All the testacea conceal them- 

 selves, as those which are marine, the purpura, whelk, and 

 all that class ; but the state of concealment is more con- 

 spicuous in those which do not adhere to rocks ; for these 

 also conceal themselves, as the pectens. Some have an 

 operculum on their exterior, as the land snails ; and the 

 alteration of those that are not free is inconspicuous. They 

 do not all conceal themselves at the same period ; for the 

 snails are torpid during the winter, the purpura and whelk 

 for thirty days under the dog star, and the pectens at the 

 same period. Most of them conceal themselves in very 

 cold and very hot weather. 



2. Almost all insects become torpid, except those which 

 dwell in the habitations of men, and those that perish and 

 do not survive for a year. They are torpid in the winter. 

 Some conceal themselves for a good while, others only in 

 the coldest days, as the bees, for these also conceal them- 

 selves. This is shown by their not touching the food which 

 is prepared for them. ; and if any of them creep out, they 

 appear transparent, and plainly have nothing in their sto- 

 mach. They remain at rest from the setting of the Pleiades 

 until the spring. Animals pass their torpid state in warm 

 places, and in the spots they are accustomed to inhabit. 



CHAPTER XVII. 



1. MANY sanguineous animals become torpid, as those which 

 are furnished with scales, the serpent, lizard, gecko, and 

 the river crocodile, during the four winter months in which 

 they eat nothing. Other serpents conceal themselves in the 

 earth, but the viper lies hidden among stones. Many fish 

 also become torpid, especially the hippurus and coracirius 

 during the winter ; for these alone are never taken but at 



