31S MANUAL OF ELEMENTARY ZOOLOGY 



-CL.ad. 



Fig. 226. — Details of the anatomy oi the swan mussel. 



A, Diagram of a transverse section through the foot, showing the principal 

 blood vessels and, hy means .it' arrows, the course of the circulation : each 

 gill is cut at an interlamellar junction. —After Howes. B, the mouth and 

 neighbouring structures from in front; C, a portion of the shell, in section; 

 D, a plan of the nervous system from above, with the visceral commissures more 

 widely parted than they arc in the animal. 



a. ad., Position of anterior adductor ; aff.br., afferent branchial vessel ; an., auricle 

 B, glandular part of kidney ; <./.,.. cerehropedal commissure; c.p.g-., cerebra 

 (cerebropleural) ganglion ; efffo;, efferent branchial vessels ; /., foot ; j\, gills 

 /'./., inner labial palp; A'.o., Rebel's organ; .7/,, mouth; mi., mantle; ncr. 

 nacreous layer; ,:/>., outer labial palp; />.-., pedal ganglion; petll., periOS 

 tracum ; /•/.//., pallia! nerve;/'/-'/., prismatic layer; r-., ventricle; :■.,., veils 



cava; v.cm.y visceral commissure; ?'.£-., visceral (parietoaplanchnic) ganglion 



