Ixngth. 



Hight, 



47.5 



51.4 



52,4 



55.4 



Length. 



Hight, 



50.5 



54. 



57.5 



62.5 



28 



It is by do means an uncommon shell in the Mounds, and the larger size as 

 compared with the recent form is seen at a glance. 



Average dimensions of ^ Uecent, 

 ten largest specimens, ( Mound, 



*—** w i » b » ™- "^ MS M<Xi speo r" s 1211 



T , . ( Recent, 



Largest specimen, [ ^^ 



Tapes sp. Plate xviii. Fig. 2. 



This species is one of the most abundant forms in the Mounds, as well as one 

 of the most common shells along the shore. It is a common edible mollusk in 

 the markets. Not being able to refer to a description or figure of the species, 

 I cannot give its specific name. It is sufficient to say that the living specimens 

 collected for comparison are of the same species as those found in the Mounds. 



The proportions of the shell have scarcely changed, though curiously enough 

 the recent ones are somewhat longer than the ancient ones, and the umbones 



are more eroded. 



Length. Hight. 



Average dimensions of ( Recent, 54.2 39.4 



ten largest specimens, ( Mound, 49.2 35.8 



Assuming length to be 100, hight in ,.- ,' i-,. 



Dimensions of largest specimen, | Mouml ' 5 ",j 



j ,, Mound, 72. 



Length. Hight. 



Recent, 58. 42. 



35. 



Dosin ia Japonica Dunker. 'Plate xvm. Fig. 6. 



This species is not common, either in the Mounds, or along the shores of the 

 Bay. A comparison of the measurements shows a change in proportions, and 

 indicates also that the ancient specimens were larger than the recent. 



Length. Hight. 



Average dimensions of ( Recent, 65.6 61.5 



ten largest specimens, ( Mound, 69.8 65.7 



