303 



legal aspects of the oyster trade, teclinirnl problems, and miscellaneous. 

 Tables are also given showing the viability of the spermatozoa in dif- 

 crent solutions of sea water; effect of strength of solution and age of 

 the oyster on the character of the development; influence of tempera- 

 ture, etc., on the rate of development of the oyster's eggs; factors 

 affecting the viability of the eggs of the oyster; effects of age, etc., on 

 the eggs. The following summary of the conclusions reached from a 

 study of the summer's records is taken from the report : 



Temperature and spaiming. — (1) From the latter part of April until .Jnne, the tem- 

 perature of the water upon tlie oyster beds at Perth Amboy, Key Port, and Oceanic rose 

 steadily from abotit 50° F. until it reached 70"^, June 1, in the Shrewsbury River, 

 ami about the middle of June iu Raritan Bay. 



(2) From this time on during the spawning season the temperature fluctuated 

 b(^t\veen 70^ and 80'^ F. 



(3) Si>awning began upon the respective beds very soon after the temperature 

 reached the seventies. 



(4) Seed obtained from the more northerly beds spawned first, and finished spawn- 

 ing relatively early. 



(5) Seed from the Chesapeake region spawned later, and was the last to show 

 spawn. 



(6) The supposed evidence for the belief that the same oyster may repeat the 

 spawning process more than once in a season Avas found insufficient. 



(7) No oysters were found in which all the eggs were capable of developing. 

 (Perhaps 70 per cent represents the most fruitful result obtained.) 



(8) Seed which matures its sexual cells early produces more fruitful results in 

 v igor and relative number of offspring than the later spawners of the same kind ot 

 seed. 



(9) At Key Port after August 7 the spawning proper had ceased; only young 

 Soutliern plants showed traces of sjiawn after this date. 



I'll ll8lolo(jy of oysters. — (10) Oysters removed from the water and left dry at ordi- 

 nary siinuiK^T temperatures remain closed for about a week. 



(11) Wlicn oysters begin to fail in the -power of holding the shell closed thej- are 

 not dead, for a stimulus will cause closure for a short time. 



(12) Such oysters are partially spoiled, through fermentative action of bacteria, 

 and are unfit for food. 



(13) After this i)oiut of weakness is reached the death of the oyster is rapid. One 

 day later it fails to respond to stimulation. 



(14) Freshening oysters increases very r.apidly the rate of weakening and decay of 

 oysters. (The life period is reduced one half.) 



(ir») After an oyster is opened the death is rapid and in proportion to the length 

 of time the oyster has been out of the water, 



(1(>) If oysters be placed in limited supjdies of sea water the postmarine life period 

 is not lengthened, owing to the breeding of infusoria and bacteria in the water. 



(17) Oysters open and shut their shells according to a rythmic or automatic law 

 (while "breathing"). 



(18) Oysters differ greatly in the rapidity of this rythm of respiration (the object 

 of which is to clear the external gill or mantle cavity of mud). 



Parasites. — (19) Sever.al species of infusoria are jtarasitic in the stomach, etc., of 

 the oyster, biit are not abundant enough to be taken account of iu culinary interests. 



(20) During tlie early portion of the spawning season there is abundantly present 

 in a large proportion of oysters an infusorial parasite (average length ^tf inch), 

 termed by us "cytohelminth" (wormlike cells). [Reference is made to an article 

 by J. Ryder in Scie^ice, vol. i, p. 567, containing a description of a parasite, named 



