IN THE INVERTEBRATA. 55 



foremost of them.' c They had/ he adds, ' a look of human 

 smartness about them, which had a kind of weirdness, from 

 being exhibited through a set of organs totally different in 

 aspect from those to which we usually look for manifesta- 

 tions of intelligence.' Some other crabs post sentinels when 

 changing their shells (Watson). 



The hermit crab seizes the dwellings of other animals the 

 shells of Mollusca killing the said animals themselves, accor- 

 ding to some authors ; but in some cases at least, when the shell 

 is inhabited by a living mollusc, waiting till its death, and then 

 tearing it out, devouring it, and taking possession of its empty 

 abode. According to Professor Alex. Agassiz, they carefully ex- 

 amine these shells, as to their suitability, before adopting them 

 as their homes, settling down ' with immense satisfaction ' in 

 those they select. The stratagems and manoeuvres, moreover, 

 of rival hermit crabs, desirous of possessing the same shell, 

 are described by a recent journalist as ' the funniest sight in 

 the world.' Further, a certain species of hermit crab shows 

 ' care and affection ' for the cloak anemone which is attached 

 to its shell home. ' He has been noticed to feed the anemone 

 with his pincerlike claws.' And when he casts his shell for 

 a larger one, ' he carefully detaches the helpless anemone from 

 the old habitation, and assists it in gaining a firm basis 

 and support on the new shell.' Hermit crabs are further 

 noted for their pugnacity and for their cunning in attack, 

 which they make at unawares. 



Pliny credited the pea crab with observation, watchful- 

 ness, adaptation, friendship, and jealousy ; but his opinions 

 have been generally regarded as Utopian, the mental 

 qualities ascribed to such an animal as fabulous. That 

 certain crabs possess all these, and many other, mental 

 aptitudes is no longer, however, a matter of doubt, thanks 

 in great measure to the opportunities of studying their 

 habits afforded by marine aquaria. And this is just one 

 of the points in regard to which the most modern and 

 advanced have proved certain ancient or classical, and sup- 

 posed ignorant, authors to be correct, both in their observa- 

 tions and inferences. 



Lobsters show mental qualities of a higher kind than 



