VII 



MOLL USCAS YSTEMA TIC RE VIE W 



19 



Lutrariidae, Myidae (My a, Corbula). Fam. Glycymeridse (Glycymeris, Saxicava 

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

 large (Solenocurtus, Gultellus, Ensis, Solen}. 



Sub-Order 6. Pholadacea. 

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



Mo H 



C 5 



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

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

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

 retractor of the foot ; Ss, partition between the two siphons ; M 3 , accessory adductor; mb, intestinal 

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

 renal funnel at u. 



HFC 



FIG. 28. 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: boring mussels (Pholas, Pholadidea [Fig. 27], Jouannetia [Fig. 281, 



