_L 



_L 







Centimeters 



Figure 71. — Organs of C. virginica seen after the removal of right valve, ad.m. — aflductor muscle; an. — anus: e.g. — 

 cerebral ganglion; f. — fusion of two mantle lobes and gills; g. — gills; h. — heart; l.ni. — left mantle; l.p. — labial palps; 

 m. — mouth; per. — pericardium; r. — rectum; r.m. — right mantle, sh. — shell; t. — tentacles. The right mantle con- 

 tracted and curled up after the removal of the right valve, exposing the gills. Portion of the mantle over the heart 

 region and the pericardial wall were removed. Drawn from live specimen. 



an undesirable term because of possible confusion 

 with the inner spaces (cavities) of the-gills. The 

 correct terminology for the latter is water tubes 

 and gill chambers. The expression mantle cavity 

 seems to be more appropriate than tlie shell 

 cavity. As to the shell liquor, the term is well 

 establislied, especially in papers dealing with tiie 

 bacteriology of the oyster and, therefore, it should 

 be retained. 



Under normal conditions the mantle underlies 

 atid adheres sliglitly to the shell, the secretion of 

 wliich is its principal function. As will be shown 

 later, this organ also participates in several other 



functions; it controls the flow of water for respira- 

 tion and feeding; plays an important role in female 

 spawning; and receives and transmits sensory 

 stimuli. 



In a living oyster the mantle cavity is always 

 full of sea water. As tlie shell is closed the surplus 

 water is ejected, but tiiat remaining in the free 

 spaces between the mantle lobes (fig. 73, m.c.) 

 keeps the enclosed organs constantly bathed in 

 water. 



Various products of oyster metabolism accumu- 

 late in the shell liquor as well as considerable 

 quantities of mucus and blood cells discharged 



GENERAL ANATOMY 



67 



