Body Spaces of Ibla Quadrivalvis. 231 



C. — Space lined by flattened epithelium, the outer part of which 

 is in contact with the body wall. 



Labrum. 1. 



Palp. 2. 



Mandible. 3. 



Inner or first maxilla. 4. 



Outer or second maxilla. 5. 



Place from which first cirrus has been removed. 6. 



Body wall. b.w. 



Cubical epithelium lining lower portion of seg- 

 mental duct. c.e. 



Irregular coelomic spaces. c.s. 



Irregular connective tissue filling up the spaces be>- 



tw^een the various organs of the body. c.t. 



Mouth of segmental duct. d.u. 



External cuticle covering body wall. e.c. 



Flattened epithelium lining space (A). e.s. 



Flattened epithelium lining upper part- of segmental 



duct. f.p. 



Granular cells lining organ opening to space (A). g.c. 



Large gland situated in the outer maxillae, with no 

 communication with the space (A), or segmental 



duct. g.l. 



Cuticle lining the segmental duct and continuous 



with that covering the body wall. i.e. 



Muscles cut longitudinally. l.m. 



Wall of mantle cavity in which body of the animal lies m.w. 



Oesophagus cut transversely. oes. 



Muscles cut obliquely. o.m. 

 Pancreatic duct passing from the pancreatic gland to 



the alimentary canal. p.d. 



Pancreatic gland. p.g. 



Segmental duct passing from space (A) to the ex- 

 terior, s.d. 



Segmental funnel. s.f. 



Supraoesophageal nerve ganglion. saip. oes. 



Muscles cut transversely. t.m. 



Nerves cut transversely. t.n. 



Tubular prominence at base of second maxilla on 



which the segmental duct opens. t.p. 



