BEHAVIOR OF LOWER INVERTEBRATES 377 



essentially the same. His results for the vertebrates do not 

 agree, however, with those of the American investigators. 



Pearse (23), by means of careful experiments, described in 

 this journal, on the crayfish, spider-crab, caddis-fly larva, and 

 crab-spider, comes to the conclusion, in opposition to Minkie- 

 wicz, that these arthropods are unable to select an environ- 

 ment which matches their own color. 



Polimanti (28) describes a case where a crab, Dromia vul- 

 garis, had attached to its back a sponge, Suberites domuncula. 

 In this case of symbiosis the initiative must be taken by the 

 crab, and Polimanti believes that associative memory plays a 

 certain part in the crab's behavior. 



In his study of the mating behavior of certain crabs, Chi- 

 dester (2) concludes that there is no evidence that sexual selec- 

 tion is involved. The males recognize the females by touch. 

 Males attempted to mate with other males and with fertilized 

 females, but never with individuals of other species. "Oppor- 

 tuneness of proximity" is the most important factor in bring- 

 ing about mating. 



Three papers of a more general character may be briefly 

 mentioned. Doflein (7) asserts his belief in the distinctness of 

 the organs of taste and smell even in water-dwelling animals. 

 The former test substances entering the alimentary canal; the 

 latter test the environment in general. In land crabs the small 

 antennae have an olfactory function, which is doubtless the 

 same in water-dwelling forms. 



Polimanti (26) describes observations made in the aquarium 

 at Naples on the periods of activity and repose in a great variety 

 of marine animals, including sea-anemones, hydroids, siphono- 

 phores, ctenophores, echinoderms, annelids, Crustacea, molluscs, 

 tunicates, cartilaginous and bony fishes, and turtles. In general, 

 he found that periods of great activity in all these animals are 

 followed by short intervals of lessened activity; the repose, 

 however, is never really complete. Temperature and light are 

 the chief regulators of activity and rest. The greatest activity 

 is nocturnal. The comparatively constant temperature of the 

 sea economizes the energies of marine animals and permits their 

 high activity. An abnormal degree of activity often occurs 

 before death. 



