276 CIVIC BIOLOGY 



Mediterranean and from North Carolina around through the Arctic 

 Ocean to San Francisco. In depth it ranges from halfway between tide 

 marks to probably 100 fathoms. Under most favorable conditions, in 

 American waters, the mussels may grow to an average length of from 

 2 to 3 inches in a year. In England, by the bed system of cultivation, 

 they require two and generally three years to attain a length of 2 inches; 

 but in France this size is secured, by the Imchot method, in a year and 

 a half. A female mussel has been observed to lay 12,000,000 eggs in 

 fifteen minutes, almost the entire substance of the animal, except 

 the heart and gills, being transformed into eggs or sperm, which are 

 thus quickly shed once a year. The spawning season varies with lati- 

 tude and with the temperature of local waters, extending from Feb- 

 ruary to September ; and since the mussels are in prime condition when 

 full of reproductive products, the beginning of the spawning season 

 should be determined for each typical bed in a locality, to the end that 

 the yearly crop may be harvested at the right time, that is, just before 

 sj awning occurs. Thus mussels may be made to till the gap in the 

 markets from May to August, when oysters are out of season ; and, in 

 fact, according to the extended investigations of Dr. Field, sea mussels 

 may be found in fair or prime condition every month in the year. Of 

 course, as long as no one knows how T good they are, this vast food 

 supply will continue to go to waste. As a matter of practical biology, 

 then, why riot arrange for a course of mussels in class banquets or 

 other entertainments, and agree to call for them frequently in local 

 restaurants and hotels. When once mussels have been tried, the de- 

 mand for them, and consequently the supply, will grow until the whole 

 country is benefited. 



Soft, or long-necked, clams Mya arenaria. This is popular for dam 

 bakes along the New England shore and far inland. Mya ranges from 

 South Carolina to the Arctic Ocean, but, unlike Mytilus, has not as yet 

 reached the Pacific by that route. Tt was, however, introduced into San 

 Francisco Bay in 1870, and spread rapidly. It appeared in Willapa Bay. 

 Washington, in 1880, was transplanted to Puget Sound a little later. 

 and has become abundant at many points in the Sound. Pacific-coasi 

 schools may well lay emphasis on this problem; for in this burrowing 

 clam we may possibly have the form best able to transform the endless 

 barren sand wastes of the Pacific into productive sea gardens. Mya can 

 be much more easily, cheaply, and quickly raised than oysters, coining 

 to market size in a year, under favorable conditions ; and the young, in 

 passing from the free-swimming, larval stage to the adult stage, often 



