FIONA. 



The nerves are distributed much as in Holts, and as in that genus there are two large 

 ones (13), which issue from the buccal mass, and are probably connected at their origin with 

 ganglia, which must be looked upon as belonging to the sympathetic system. Immediately 

 on emerging from the buccal mass, they are connected to the buccal ganglia at their point 

 of union with the gastroesophageal, and then arching upwards, go to supply the glands of 

 the papillae. 



There is also a single nerve (14) given off from the delicate collar, the ends of which 

 are united to the under surface of the branchial ganglia. This is a visceral nerve, and 

 similar to that in Eolis. Another nerve (15), apparently supplying the genitalia, 

 has been observed ; this seems to come from the right branchial ganglion at its union 

 with the pedial. These two nerves, which, however, require further examination, probably 

 represent those that come from the visceral ganglion in Doris, and which, in that genus, are 

 distributed to the sympathetic ganglia of the digestive, reproductive, respiratory, and 

 circulatory organs. 



EXPLANATION OF THE PLATE. 



Fig. 1. Side view of Fiona no bills : — a penis, partially excerted; b, orifice leading to the female and 

 androgynous parts. 

 &. Dorsal view of the same, the papillae of one side being removed: — a, anal nipple; b, renal 

 orifice ; c, heart ; d, great posterior branchio-cardiac vessel, raised above the general surface ; 

 e, small branches, likewise raised above the surface, leading from the papillae to the same ; 

 /, scars formed by removing the papillae. 



3. Two of the papillae enlarged: — a, small raised vessel leading from the papilla? to the great 



branchio-cardiac trunk ; b, puckered membranous fringe with the efferent vessel running 

 down its margin. 



4. General view of the viscera, seen from above : — a, buccal organ ; b, oesophagus ; c, stomach ; 



d, intestine; e,e, hepatic- ducts, leading from the great lateral hepatic channels within the 

 skin ; /, one of these channels laid open, exhibiting the canals from the papillae opening into 

 the same ; g,g, folliculated glandular bodies in connexion with the anterior portions of the 

 great hepatic channels ; h, gland-like substance in connexion with the hepatic channels ; i, 

 some of these channels laid open ; j, a portion of the right mucus-gland ; k, penis ; /, testis : 

 m, ovary ; n,n, mucus-gland in connexion with the female channel ; o, o, pericardial cavity, 

 seen in section ; d ', o' , floor of the same ; p, ventricle ; q, auricle ; q', portion of the same 

 attached to the great posterior branchio-cardiac trunk-vessel ; r, r, the same vessels longitu- 

 dinally divided; s, portal heart, opening through the floor of the pericardium; t, renal 

 orifice ; u, cerebral ganglions. 



5. Side view of buccal organ : — a, anterior extremity ; b, oesophagus ; c, horny jaw ; d, muscles 



for advancing the buccal organ ; e, lingual sheath. 



6. Inner view of one of the jaws : — a, cutting edge ; b, point of articulation ; c, expanded process 



at the dorsal margin for muscular attachment. 



7. Two of the lingual plates. 



8. View of two glandular organs lying beneath the stomach, supposed for the purpose of lubri- 



cating the foot : — a, oral opening ; b, thickened anterior margin of the foot ; c, c, glandular 

 organs ; d, d, their duct. 



