ABBREVIATIONS. 



0. anus. 



oa. - anterior adductor mu>cle. 



b. - 1>\ >-u>. 



bg. bys-sal gland. 



IHJI: byssal groove. 



tut. byssal notch. 



d. dissoconch. 



di. distal cud. 



i r. " car." 



/. foot. 



fc. foot cleft. 



fg. foot groove. 



fl. flagellum. 



//. foot rotrai-tnr imi.-cl 



g. gills. 



h. hinge line. 



ht. heart. 



1. intestine. 

 iy. inner gills. 

 I. liver. 



//). -- labial palps. 

 in. - mantle. 



inf. mantle flap. 



int. mouth. 



o. otocy.-t. 



og. outer gills 



or. ovary. 



pa. posterior adductor mu-rle. 



pc. polar cells 



p<l. prodissoconch. 



pi. plicated growth. 



pin. primitive mouth. 



pr. proximal end. 



ps. pseudo-siphon. 



r. retractors of velum. 



s. stomach. 



S(J. shell gland 



t. tentacles. 



te. teeth. 



ts. testis. 



v. velum. 



'in. visceral mass. 



yl. yolk lobe. 



