OYSTER BOTTOMS IN MATAGORDA BAY. 81 



the volume of the head of an ordinary pin. The method of extract- 

 ing the food from the stomach is admittedly crude and inexact, and 

 undoubtedly a considerable proportion of the stomach contents arc 

 not withdrawn, but even so the results show that the volume of food 

 at any given time must be very much smaller than has heretofore 

 been suspected. Basing the opinion upon the known rate of growth 

 of oysters, and under the extreme assumption that the food is con- 

 verted into o} T ster bulk for bulk, the rate of ingestion must be vastly 

 more rapid than assumed by Grave or suspected by other investiga- 

 tors. An oyster whose body is 2J inches long will, when in good 

 condition, have a bulk of 12,000 to 15,000 c. mm. Assuming that the 

 normal stomach content is one-fourth cubic millimeter, twice that in- 

 dicated above, and adopting Grave's statement that this normal con- 

 tent is ingested in four hours, it would require from 800 to 1,000 days' 

 constant feeding for the 0}^ster to procure food in bulk equaling its 

 own. We know that oysters on the gulf coast will grow to the 

 volume mentioned in less than two years, sustaining the while all of 

 the energy expenditures of metabolism and mechanical movement. 

 The matter merits investigation and the revision of the assumptions 

 of previous investigators, and the writer contemplates its considera- 

 tion in the near future. 



SPAWNING OF OYSTERS. 



The spawning of oysters consists, in brief, of the discharge of eggs 

 from the female and spermatozoa from the male to meet and fuse 

 in the surrounding water. The fertilized eggs develop into minute 

 embryos, each furnished with a little brush of cilia or hair-like proc- 

 esses which vibrate in rhythm and propel it feebly through the water. 

 After a time varying with the temperature of the water the embryos 

 develop a tiny shell, which by its weight eventually precipitates 

 them to the bottom, where, if they fall upon a suitable clean, firm 

 support, they attach and grow into spat, but if not they speedily 

 die. As their own powers of locomotion are inconsiderable, the wide 

 distribution of the young oysters in their swimming stage is depend- 

 ent upon the currents. 



Oysters in the spawning condition are of a peculiar creamy color, 

 with branching lines traced over the surfaces of the body. When 

 they are cut the ripe genital products at once exude from the wound, 

 but if the shell be opened carefully and a gentle pressure exerted 

 upon the body they will be discharged from a definite opening lying 

 below the muscle (usually called by oystermen the " eye " or 

 "heart ") which extends between the two valves. This is the pore 

 from which they flow in the normal process. Ripe oysters in the 

 language of the oystermen are aptly described as " milky." 



