FACTS Al'.ol r \\"i;i.l. KNUW.N ANIMALS. 



85 



while tlial of luiropr is s|KrirRially (lilUivul and known as 

 Ostrea edulis L. 



Fig. I. — Gettealogy of the hofsc : /^Orohippus; ,-, Miohippii^; </, Pliohippus ; 

 (T, Equus. (After Marsh. ) 



The oyster has generally been considered lieiinaphrodite, 

 /. (.. eonihining both sexes in one individual ; and the 

 young are said to be at first hatched and then [)rotected inside 

 the mantle cavity of the i)areut. Though this may be true 

 of the Euro])ean species, Dr. \V. K. Brooks, of Johns Hop- 

 kins Tniversity, by recent admirable researches, has clearly 

 shown that our American oyster has tlic sexes separated 

 antl that the young are hatched in the free water, and have 

 to take their chance without parental care or protection. 

 Independence is of quicker development in this free coun- 

 try as well in the oyster as in man. Without going into 

 anatomical details I would state that what we know as the 

 " fat " of the oyster forms the reproductive part. The milky 

 llui<l fidin it, in a gravid female, when spread out in a thin 

 tilm will ^how innumerable white ovarian specs, even with- 

 out the aid of a microscope ; while that iVom a well-devel- 

 oj)ed male is more homogeneous and moic adhesive. This 

 tluid is exj)elled in the water at the bree<]ing season, and 

 the egg, once adrift, must meet a male cell or perish. The 

 average number of (»va produced by a single female is per- 

 haps ten millions, and a large sized cme may produce as 

 many as sixty millions. So you can imagine at what an 

 immense rate they would multiply did they not, in the egg 

 state, form the principal food of hundreds of other creatures; 

 and had they not, in all stages of growth, numerous ene- 

 mies. 



l*robablv not w\^^xv than one in -cveral millions reaches 



