MOLLUSCS. 



281 



jPlG. 305. — Saxicava 

 ntgosa. 



and implements of the former inhabitants. In these hea^js on the coast of Maine, the 

 bones of the now extinct great auk have been found. 



However eaten, whether raw, or in a chowder, or fried, the clam is good, but best 

 of all is the clam-bake, where a long-continued fire heats the rocks red hot. Then the 

 cinders and ashes are swept away, a thin layer of rock-weed is laid on the hot stones, 

 the clams placed in the centre and covered with more of the rock-weed. The steam 

 generated cooks the clams in the most perfect manner. 



A second species of Jifya, M. truncata, occurs on our coast, and but one other is 

 known in the world. Mi/a truncata, instead of being rounded at both extremities, is 

 truncated behind, while in the living specimen the epidermis is extended in the shape 

 of a tube, some six or seven inches in length, from the. posterior edges of the shell. 

 This species lives below low-water mark, and is not common south of Eastport. On 

 the English shores it is more common than Mi/a arenaria. 



The species of Saxicava bore into hard mud, stones, etc., and have very irregular 

 and greatly distorted shells, so that specific limits are far from certain. Probably our 

 only species is that figured, Saxicava arctica, but several others 

 have been described upon the variations of this form. Indeed, 

 Woodward states that no less than five genera and fifteen species 

 have been made upon the form known as S. ntgosa, and since this 

 and S. arctica are probably the same, the synonymy of this protean 

 species is something awful to contemplate. In places where lime- 

 stone is abundant, Saxicava bores holes in it to the depth of about six inches, and as 

 it is not at all careful where it goes, it 

 not infrequently cuts across the burrow 

 of another individual. When a specimen 

 dies the soft parts decay, but the valves 

 remain in the burrow, and another indi- 

 vidual occupies the same burrow, seating 

 itself " between the valves of its prede- 

 cessor. In this way four or five pairs of 

 sliells may be frequently seen nested one 

 within the other." 



Panopcea is a genus of large shells, 

 the animal of which closely resembles 

 Saxicava. Panopcea norvegica is a boreal species, specimens of which are occasionally 



found in the stomachs of 

 fishes ; the sliell is covered 

 with a thick epidermis. 



Glycimeris siliqiia is the 

 only species of the genus 

 known, and j^resents several 

 noticeable peculiarities. It 

 is covered with a thick, 

 glossy -black epidermis, 

 while the interior of the 



Fig. 307. — Glycimeris siliqua. , . , i ■ n j 



thick valves is rendered 

 very irregular by the great deposition of calcareous matter seemingly without rhyme 

 or reason. The animal is much. larger than the shell, and the soft parts c9,nnot be 



Fig. 306. — Fanopaia norvegica. 



