EECEEATIVE SCIENCE. 



99 



tlie claws were small, in proportion, and by- 

 no means well-formed ; no donbt, tlie oyster- 

 shells must have impeded their free action, 

 at least to some small extent. The colour of 

 the carapace was paler than usual, and its 

 texture was brittle. The contents of the 

 encasement, that is, the body and muscles of 

 the crab itself, were emaciated, the flesh 

 was flabby, and, altogether it was unfit for 

 the table; it was a very "poor crab" in- 

 deed, probably half- starved, owing to its loss 

 of activity. Now, our inference is this, viz., 

 that at a certain period of its existence, 

 after acquiring a new suit of armour, the 

 crab in question became sickly, a regular 

 and confirmed invalid, from what cause or 

 causes we pretend not to say; that it 

 lurked quietly in some sick-room, but not 

 a very secluded one, not a deep recess; 

 and that, stirring but little, the oyster-spat 

 dropped upon it, developed, grew, covered it, 

 and at length concealed it in the oyster-bed, 

 among a crowd, to which it belonged not, 

 and where it was, so to speak, a stray sheep, 

 a wanderer from its own domains. This, we 

 know, that it was obtained by the oyster- 

 dredger, and certainly it had no business in 

 such a locality. Perhaps the very locality 

 into which accident introdiiced it caused its 

 sickness. How long it might have lived had 

 not the ruthless dredger hauled it up, we 

 cannot tell ; sure, however, are we that, what 

 with five oysters, and the sand-agglutinating 

 sea-worms, it must have dragged on a miser- 

 able, back-burdened existence. " Call you 

 this backing your friends ?" 



JN"ow the present is not the only instance 

 of a crustacean covered by shelled mollusca, 

 or sheU-fish, that has come under our observa- 

 tion. A few years since, a living, good-sized 

 lobster was presented to us for examination, 

 the whole backplate of which was a mussel- 

 bed ; the mussels stood u.pright in dense 

 array, forming a compact phalanx, a hedge- 

 hog-back of mussels, each rooted to the spot 

 where it had fixed itself in its primitive and 



imperfect condition. They were of large size, 

 indeed of the largest, a sufficient token of 

 their long quietude. Strange and interesting 

 was the spectacle. 



In the British Museum, and also in some 

 of the local museums, specimens of lobsters 

 and crabs bearing oysters and mussels, toge- 

 ther with other burdensome parasites, are 

 preserved as curiosities, and well worthy are 

 they of attention. They prove that causes 

 which we do not understand arrest the growth 

 of crustaceans, not only in maturity, but in 

 their earlier stages of existence, and also that 

 this arrest of growth is by no means incon- 

 sistent with a certain degree of vital energy. 

 In the case of the crab figured, the animal 

 had certainly not undergone exuviation for 

 five years, was in a sickly state, but in that of 

 the mussel-backed lobster no appearance of 

 sickness was observable ; it was of proper 

 weight, and thoroughly active, yet the mussel- 

 bed must have been a fixture for at least 

 three years. True it is that it was less in- 

 commoded by its burden than our poor crab, 

 inasmuch as the large caudal portion (its main 

 mass of muscles) was not incumbered, leaving 

 it to its full liberty of movement. Strange 

 that it should not have cast ofi" its armour 

 for so long a period ; not more strange, how- 

 ever, than many other points connected with 

 the history of the crustaceans, into which 

 we must not now attempt to enter. 



W. C. L. Maetin. 



FALLING STARS. 



Faliing STAE3 furnish good practice to ama- 

 teur astronomers for the calculation of their 

 distances from the earth, as well as their rate 

 of motion through space. As they are usually 

 abundant about the middle of November, 

 we remind our friends in good time, to enable 

 them to prepare their minds on the subject 

 of parallax. 



