( 87 ) 



is'to be noted, that thefe fifhes, by reafon of the leno-th of their 

 fliells, are each provided with two of thofe tendons, or finews, where- 

 as oyl^ers and^ fait- water Mufcles have only one. N O P is a thin 

 membrane, or fkin, lying folded up, with which the whole infide of 

 the empty fliell had been covered, or lined. 



O R S is one of the two receptacles wjierein the eggs, as they ad- 

 vance to maturity, are lodged, and which parts do then become fwol- 

 len thereby, but at other times they are very thin ; thefe parts, in oy- 

 Hers, are called the beard; T V is the other oftheie receptacles, 

 which, in oyfters, is alfo called the beard ; and in thefe receptacles, 

 I did not obferve any thing particularly remarkable, except their 

 wonderful make. 



W X Y is a iblid flelliy part, wrinkled on the outer edge, and in 

 rerp36l of the other parts of the fi(h, very ftrong ; this part, as I 

 have already mentioned, the Mufcle protrudes, or thrufts out of its 

 fhell, to a conridera))le length, when it prepares to change its place; 

 and when at reft, it generally has a fmall portion projecting out of 

 tiie fhell ; but if it be touched, though very lightly it inanediately 

 withdraws it. The fpot marked with the letter Y, is the place where 

 the eggs lie before they are depofitcd in what we call the beard ; and 

 if an incifion be made in this part, the eggs, with a watery liquor, 

 iOue forth. 



Some of thefe Mufcles I o])ened in the prefence of the Engraver, 

 in order, that as foon as I had taken fome of the young ones out of 

 their receptacles, he might make a drawing of them, for, were they 

 fuffbreJ to ftand but a, few hours, their true figure would be loft. 

 The unborn Mufcles being put into a glafs tube, and placed before 

 the microfcope, I faw with afloniHiment a molt pleating fpedacle, 

 for every one of them, each in its particular membrane, or covering 

 had a flow circumvolution, and that not for a {hort fpace of time, 

 but fuch turning round or rotatory motion was obfervable for three 

 hours afterwards, and it was the more curious, becaufe the young 

 Mufcles, during the whole of their motion, conftaiitly kept in the 



