OF MASSACHUSETTS. 127 



considered as spheres with intervening spaces, whereas in reality they 

 are packed together in distorted shapes in the ovary. This perhaps 

 offsets the second error. (2) In the second part of the computation 

 the coils of the digestive tract, left in the ovary, are not allowed for, 

 and with the outer covering are included in the total volume. (3) 

 Another error arises from the fact that all the eggs may not be as 

 large as the mature ones. (4) There is also the room taken by the 

 egg capsules and tissues. Whether these errors offset each other, or 

 whether the one-fourth allowance is correct, it is impossible to state. 

 However, for all practical purposes the method and count are accurate 

 enough. 



Method of determining the Number of Spermatozoa produced by 

 the Average Scallop in One Season. — The method of finding the 

 number of spermatozoa in the testes of a scallop is practically the 

 same as in computing the number of eggs in the ovaries. It takes 260 

 spermatozoa heads placed lengthwise to measure 1 millimeter, and 500 

 heads placed side by side to measure the same distance. It there- 

 fore takes 65,000,000 to make a volume of 1 cubic millimeter. By a 

 generous allowance of 15,000,000,000 for tails and tissue there would 

 still be left 50,000,000,000 spermatozoa to every cubic centimeter. It 

 was found that the size of the testes and the ovaries in the same scal- 

 lop was practically identical, and that the testes of a 40-millimeter 

 and a 68-millimeter scallop measured % cubic centimeter and 1% 

 cubic centimeters respectively. Thus the average 40-millimeter scallop 

 is capable of producing 25,000,000,000 and the 68-millimeter scallop 

 71,400,000,000 spermatozoa. 



Methods of recording Spawning. — A variety of methods were 

 employed in determining the spawning of the scallop. Chief among 

 these were (a) general observation at the various scalloping localities 

 of the coast; (6) microscopic examination of the eggs from the ovaries 

 at different seasons; (c) the plankton net; (d) recording the color 

 of the egg sac by color charts; (e) appearance of the young set in 

 the different localities and at different years; (/) individual 

 spawning. ( 



(a) General Observation. — • This method was chiefly followed in 

 1905 and 1906. Trips were made to the various localities, such as 

 Edgartown, Nantucket, Buzzard's Bay, Cape Cod, and the condition 

 of the egg sac of a large number of scallops noted both by eye and 

 by microscopical examination. The condition of the sexual products 

 were then classed under three heads, (1) immature, (2) spawning, (3) 

 spawned, according as to whether the eggs had been liberated at that 

 date. By making several trips during the summer a general idea of 

 the duration of the spawning season and its variation in Massachusetts 

 waters was obtained. This method, though naturally inaccurate in the 

 minor details, nevertheless proved extremely useful. 



