MOLLUSCA SYSTEMATIC 



UNIVI 



CtU'r.. 



Lutrariidae, Myidae (Afy", Corbula}. Fam. Glycymeridae (Glycymeris, Saxicava 

 [boring mussels]). Solenidse : shell with anterior and posterior cleft ; foot very 

 large (Solawcui-tus, CultcUus, Ensis, Solen). 



Sub-Order 6. Pholadacea. 



Dimyarian with closed mantle and well-developed siphons. Foot varies, and is 

 M, Ifz? ffa jft 



j/^^Li / 



FIG. 27. Anatomy of Pholadidea, left aspect (after Egger). Lettering as before. In addition, 

 AJXJ, Npp, anterior and posterior nerves of the mantle edge ; mo, anterior aperture of mantle ; Ks, 

 sac of the crystalline stylet ; Ki-, branchial vein ; ol, anterior upper mantle lobe ; Rpp, posterior 

 retractor of the foot ; Ss, partition between the two siphons ; M s , accessory adductor ; mb, intestinal 

 caecum ; x, pericardial section of the kidney, which opens into the pericardium by means of the 

 renal funnel at /. 



M, 



HFC 



FIG. -23. Anatomy of Jouannetia Cumingii, left aspect (after Egger). Lettering as in 



last figure. 



sometimes rudimentary. Shell open, often having accessory pieces added to it. 

 Fam. Pholadidse: boriag mussels (Pholas, Pholadidea [Fig. 27], Jouannetia [Fig. 28], 



