MACROURI. - 215 



I am not aware that the Fresh water Cray-fish is naturally an in- 

 habitant of Scotland ; but a brood was introduced, thirty-five or forty 

 years ago from England, by the proprietor of New Posso, in the county 

 of Peebles, which, together with the progeny, has been extirpated for at 

 least twenty -five or thirty years. 



It is from the ova of the cray-fish that a learned naturalist, Eathke, 

 hath demonstrated the progressive development of the embryo. Amidst 

 many attempts to accomplish the like from a number of the other crus- 

 taceans, I have been uniformly unsuccessful. It is true that the general 

 form and position of the subject included is sufficiently exposed, but the 

 integuments are never refined enough to shew the regularity, the true 

 arrangement, or modification of the metamorphosing parts. 



The genuine cray-fish is said to dwell chiefly in muddy streams, 

 whereof, from tlie mountainous nature of the country, we have very few 

 in Scotland. 



§ 2. AsTACUs MARiNUS — The Common Lobstei-. — Plate LVIII. LIX. 



No animal is more familiar than the Common Lobster: its form and 

 habits, together with the wounds it is prone to inflict on unguarded cu- 

 riosity, are sufficient to imprint its recollection on the memory. At the 

 same time, there is scarcely any other of its kind whose history is less 

 known. 



It is everywhere sought as an epicurean delicacy, and sometimes 

 purchased for high and unreasonable prices. Besides, from the absolute 

 alteration of colour under culinary opei'ations, the animal is viewed as 

 a curiosity. 



The Lobster attains considerable dimensions in Scotland ; and, 

 where it can escape the wonted persecutions of mankind it certainly 

 lives many years. 



In the middle of December, I procured a fine specimen of a living 

 female, laden with a profusion of roe. It extended twenty-two inches 

 in length, from the tips of the antennae to the caudal fringe. Of this, 

 the carapace or body-segment, which is the criterion of dimensions in a 



