474 THE AQUARIAN NATURALIST. 



threads of byssus, very closely resembling those of 

 the mussel, only much shorter, and of a coarser tex- 

 ture, whereby the creature fixes itself to any sub- 

 stance that may be in its neighbourhood, whether it 

 be a stone, a piece of coral, or any other solid object ; 

 and after storms they are not unfrequently found cast 

 up among the rocks, where there were none the day 

 before, and yet fixed by their threads as securely as 

 if they had occupied the situation for months. Their 

 byssus is produced exactly in the same manner as 

 that of the mussel ; only the organ with which they 

 manufacture it is not so long, and has a wider groove, 

 on which account the threads are necessarily thicker 

 and shorter. 



According to Dioscorides, whose dictum for many 

 centuries received implicit assent among the disciples 

 of learned antiquity, " the Escallop is engendered of 

 the dew and air," as indeed was supposed to be the 

 case with bivalves generally. Fortunately, in these 

 days they seem to have changed their manners in 

 this respect, and the aquariist may now observe them 

 produced from eggs, which, owing to their brilliant 

 orange colour, are very conspicuously visible. These 

 eggs, when first laid, are received into one or other 

 of the pairs of branchial laminae, which become much 

 swollen by their presence. It is in this situation that 

 they are hatched, and give birth to a progeny totally 

 dissimilar from their parents, although already en- 

 closed in a pair of shells. They are indeed, on their 

 first emergence from the egg, extremely active, and 

 swim vigorously about in all directions by means of 

 two prolongations derived from the mantle, which 



