MOLLrSCS. 



SlOll nl 



liing.' 1 1 



marks the limit of tlie tliic-kenod edge of the mantle, and in one large group of shells 

 a portion of the pallial line makes a re-entrant angle. This is the pallial sinus and is 

 found ojily in bivalves with a siphon, 

 where it marks the place of attachment 

 of the muscles of that organ. 



The classification of the acejihalous 

 mollusca is still in a \ery unsatisfactory 

 condition. In the system of Laniai'ck 

 the group was divided into two suli- 

 classes, based upon the number of ad- 

 ductor muscles, those in which only one 

 of these muscles was present forming 

 the Mononiyaria, while those with two 

 were called Dimyaria. Woodward, who 

 wrote one of the most valuable manuals 

 of conchology which has as yet ap- ri«- .-' 

 peared, used the presence or absence 

 of siphons as a means of division, those 

 where no sijjhon was formed being the Asii)honi(hT, the others foi-ming the Siphonida. 

 The Siphonicht in turn were subdivided, according to tiie presence or absence of a pal- 

 lial sinus, into the Sinupallialia and the Integropalliala, respectively. With each of 

 these systems many grave faults may be found, and hence, for our purpose we will 

 divide the Acephals directly into families, without the intervention of sub-classes ami 

 orders, and other intermediate divisions. 



In economic importance the Ostkeid.e, the oyster family, stands pre-eminently 

 first. The characters of the family, taken in its older and broader sense, are as fol- 

 lows : The two valves of the .shell are uneipLal, the hinge is without teeth, and, as a 

 rule, the single adductor is nearly median in its position. The two halves of the 

 mantle are free from each otlier, and the borders are fringed with small tentacles, and 

 the foot is rudimentary or even entirely absent. 



The genus Ostrea has a shell so irregular that specific limits are very poorly 

 deKned. The left valve, which is attached to some submerged object, is hollowed out 

 to receivi' the body, while the u])]ier right v.-ilve is nearly flat. With us Americans, 

 OMrea ririjliiidua is the important form, and to it most of the succeeding account 

 applies. In Eurojie the species which form the bulk of those eaten are 0. eJidis and 

 0. anijuliitd. 



Ostrea virf/iniana extends, on our Atlantic coast, from the Gulf of St. Lawrence 

 to the Gulf of Mexico. In the former region the oysters are found from the Bay of 

 Chaleur to Prince Edward's Island. The beds arc small and in many places seem to be 

 decreasing. The oysters found here are usually large. These beds are separated 

 from the nearest natural living beds to the south, by a thousand miles of coast line, 

 but between these jioints evidence is abundant that in former times the gap was far 

 less, for remains of extinct beds are found all along the coast, from Mount Desert 

 Island to Cape Cod. At Damariscotta, Maine, was once a large bed which furni.shed 

 the Indians with the means of many a feast. Here, year after year they caiTie, and 

 with the refuse shells tliey formed huge heaps which to-day are the delight of the 

 archteologist. The oysters in these "l^jokkenmoddings " (a Danish term meaning 

 heaps of kitchen refuse) were of enormous size, one having been found at Damaris- 



VOL. I. —17 



