21 

 PLATE XI. 



THE EARTH-WORM continued. 



DISPOSITION OF INTERNAL OUOANS 

 FIG. 1 and DIAGKAM 



Mouth. 



ALIMENTARY SYSTEM. 



BLOOD SYSTEM CIRCULATORY 



Cut end of muscular pharynx. 

 1 Gullet, 



Crop, a dilated portion of gullet. 

 Gizzard, whitish, thick, and muscular. 

 Intestine leading straight to anus, and covered with a brownish 



mass supposed to be the liver. 



f Colourless corpuscles in perivisceral cavity two shown. 

 Pseud-haemal vessels contractile, and therefore circulatory 

 Supra-intestinal vessel (L. supra, above). 

 Sub-intestinal vessel (L. sub, under). 

 Sub-neural vessel. 

 Cominissural vessels connecting supra-intestinal and sub- 



AND RESPIRATORY . . \ intestinal vessels. 



Dilated commissural vessels in the region of the reproduc 

 tive organs, the so-called hearts. 



Coloured fluid without corpuscles contained in pseud-hsemal 

 vessels acts as an oxygen-carrier, and is therefore respira 

 tory in function. 



RENAL SYSTEM Segmental organs in pairs in each segment. 



Cerebral or prse-oral ganglia connected by commissural cords 



embracing the pharynx with the 

 NERVOUS SYSTEM . . . . ^ Sub-cesophageal or post-oral ganglia which form the anterior 



extremity of a 

 - Chain of ganglia extending to end of body. 



f Ovaries and oviducts. 



REPRODUCTIVE SYSTEM . . 1 , 



( iestes and vasa deferentia shown in fig. 2. 



Fias. 2, 3, 4. RENAL AND REPRODUCTIVE SYSTEMS 



Segmental organs with internal ciliated opening and external pore (tig. 3). 

 f Anterior pair of spermathecae. 

 ( Posterior pair of spermathecae. 

 f Anterior pair of bilobed testes. 

 ( Posterior pair of testes. 

 f Anterior reservoir of testes with duct. 

 ( Posterior reservoir of testes with duct. 

 Common vasa deferentia. 



Capsulo-genous glands for secreting egg-capsules. 

 Ovaries. 



Oviducts with wide ciliated internal opening and external opening (fig. 4). 



FIG. 5. Ovary with ova. When laid the eggs are enclosed in clusters within a chitinous case, each egg 

 consisting of Vitelline membrane. 

 Vitellus. 

 Germinal vesicle. 

 Germinal spot. 



Spermatozoa from Spermatheca. 

 CLASSIFICATION 



Sub-Kingdom Annelida (L. annulns, a ring), because the body is segmented ; without jointed 



limbs ; nervous system forms a ring round gullet, followed by a ventral chain of ganglia. 

 Natural Order Oligochae ta (Gr. oligos, few ; chuite, hair), because the bristles are in rows, not 



tufted. 



Genus Lumbricus. 

 Common Name Earth-worm. 



