276 



CHAPTER U.— continued. 



ANALYTICAL INDEX. 



Perhaps the largest Scottish shell animal, the crustaceous race 



excepted, ..... page 133 



Rudely resembles a flattened heart, . . . . ib. 



Two specimens each five inches in length, . . . ib. 



Description, ...... ib. 



Usually sunk in the sand, of which it swallows an enormous quantity, 1 35 



Plate XXXII., explained, .... ib. 



§ 3. Spatangus (flavescens), — NivEUS, . . . . ib. 



Fine delicate-looking animal, somewhat heart-shaped, . ib. 



Largest specimens two inches and a-half in length, . . ib. 



Three or four kinds sufficiently definite, . . . 136 



Form, organs, &c., ...... ib. 



Burrows in the sand at various depths, — rather a scarce animal, ib. 



Plate XXXIIL, explained, ..... 137 



Miscellaneous remarks regarding the term Echinodermata, ib. 



CHAPTER III.— Crustaceans, ...... 139 



Subdivision resting on analogy essential, ... ib. 



The observer ought to preserve an accurate record of facts, . ib. 



Crustacea form an immense class, . . . 140 



Great variety, and as yet imperfectly known, . . ib. 



The shelly covering leads to singular physical consequences, ib. 



It is frequently renovated, ..... 141 



Shells of living crustaceans of various colours, . . ib. . 



Some naturalists have viewed the animals as near akin to insects, ib. 



Shell composed of numerous parts or segments, . . ib. 



Crustaceans provided with a number of limbs, by which the genera 



is founded, ...... 142 



The Decapodes, or those with ten limbs, the most familiar, . ib. 



Motion of the crustaceans is chiefly walking or running, . ib. 



Harbour generally among rocks and stones, . . . ib. 



The senses, especially of sight and smelling, very obtuse, . ib. 



Generally carnivorous, ..... 143 



A few genera confine themselves to land vegetable products, ib. 



Some of them of a most contentious nature, . . . ib. 



The Actinia a deadly enemy, .... ib. 



Frequent change of water essential to the preservation of specimens, 144 

 In the living animal the claws are open and the tail closed — the 



reverse is the case when death ensues, . . . ib. 



