DORIS. 



Fig. 12. Digestive organs of D. pilosa : — a, channel of mouth; b, buccal mass; c, gizzard-like 

 portion of the same ; d, salivary glands ; e, oesophagus ; /, membranous crop at the 

 commencement of the same; g, dilated portion of the same; h, liver laid open, exposing 

 the track of the alimentary canal ; i, hepatic ducts opening into the anterior portion of 

 the stomach ; j, stomach ; k, pancreatic organ opening into posterior portion of the 

 stomach ; I, I, intestine ; m, anus. 

 13. Digestive and renal organs of D. bilamellata, the latter organ laid open : — a, channel of 

 the mouth ; b, buccal mass ; c, muscular gizzard opening into the same ; d, external 

 sac for the reception of the tubular portion of the tongue; e, salivary gland; /, oesophagus; 

 g, pancreatic organ opening into the stomach; h, h } intestine; i, anus; j, liver; k, k, renal 

 organ laid open longitudinally to expose network of vessels on its walls ; I, a bristle 

 passed into the renal cavity through external orifice ; m, ventricle of heart ; n, auricle ; 

 n , aorta ; o, portal heart opening into pericardium ; p, portion of the floor of pericardium 

 attached to the margin of orifice leading into portal heart ; q, orifice leading from peri- 

 cardium into portal heart. 



Plate 2. 



1. General view of the viscera of D. tuberculata, partially separated, the arterial system being 

 injected : — a, buccal mass ; b, gullet ; c, stomach ; d, d, intestine ; e, anal nipple ; 

 /, liver mass ; g, hepatic duct ; h, salivary glands ; i, pancreatic organ ; j, retracted 

 penis ; k, k, the two portions of the mucus-gland in connexion with the female channel; 

 I, spermatheca ; m, copulatory channel or vagina, leading to the same ; n, accessory 

 spermatheca ; o, root of the aorta, the heart having been removed ; branches from the 

 great systemic artery may be seen passing to all the viscera; p, portal heart; q, q, renal 

 organ, with the hepatic or renal arteries lining and appearing through its upper wall; 

 r, a bristle passed into the renal cavity through the external orifice ; s, s, a glandular 

 body apparently in connexion with the vascular system ; t, the supra-cesophageal ganglia 

 with various nerves passing off from them. 



2. Entrance to the buccal mass of D. pilosa, seen in front, the channel of the mouth having 



been removed : — a, a, buccal lips ; b, b, prehensile collar in connexion with them ; c, the 

 free extremities of the rudimentary jaws ; d, d, portion of the lining membrane of the 

 channel of the mouth. 



3. A portion of the prehensile collar, showing the arrangement of the spines. 



4. A group of the spines more highly magnified. 



5. Two of the spines still more highly magnified. 



6. The rudimentary plate or jaws entirely exposed : — a, their free extremities ; b, the portion 



buried in the buccal lips. 



7. Generative organs of D. tuberculata, removed from the body and unravelled : — a, channel 



of the penis leading to external orifice ; b, retracted penis ; c, c, testis ; d, ovary spread 

 over the liver ; e, e, oviduct • f, dilated portion of it ; g, the point where it communicates 

 with the testis ; h, h, semipellucid portion of the mucus-gland in connexion with the 

 female channel; i, opaque portion of the same; j, female channel leading to external 

 orifice ; k, spermatheca ; /, its duct leading to the oviduct ; m, accessory spermatheca ; 

 n, vagina, or copulatory channel leading from external orifice to spermatheca. 



