1 86 The Naturalist of Cumbrae. 



depths of the ocean to the surface, the conditions 

 of pressure and temperature are so greatly and 

 abruptly changed that the creatures cannot as a rule, 

 by any means yet invented, be observed alive or in a 

 set of circumstances natural to them. But shore- 

 frequenting creatures, and those living at moderate 

 depths, can often be induced to make themselves at 

 home with the naturalist for long periods, displaying 

 their various beauties and singularities of habit, which 

 could in no other way be observed. A wholesome 

 discontent with inanimate specimens may be inspired 

 in the rising generation of naturalists by the record 

 above referred to and now to be quoted : 



" Mr. David Robertson exhibited a living specimen 

 of Corystes Cassivelaunus, which had been in his 

 possession upwards of seven months, during which 

 time he had favourable opportunities of observing its 

 habits. In bringing these under the notice of the 

 society, he remarked that this crab, in burrowing 

 into the sand, lies buried for weeks without seeking 

 to change, and that the antennae clasp into each 

 other when the creature is so situated, forming a tube 

 through which it breathes, and otherwise maintains 

 a communication with the surface. Mr. Robertson 

 also stated that he had seen the ova cast up through 

 this opening the inference being that the animal 

 had placed it, by means of its claws or pincers, within 

 the influence of the current. Mr. Robertson likewise 

 exhibited specimens of Nereis bilineata> and made 

 some remarks upon its habit of living in univalve 

 shells, in company with hermit crabs." The masked 

 crab, on which the above observations were made, 



