FIc. 
> 
EXPLANATION OF PLATE XVI. 
Atopos (Parapodangia) gravelyi, n. sp. 
1.—Side view of the mature specimen (nat. size); o, male 
aperture. 
Ia,—Side view of the smaller specimen (nat. size); the 
proboscis is protruded. 
1b.—Ventral view of the head. 
Ic.—Side view of the head. 
2.—Transverse sections of the body; a, through the 
middle; 6, about 1°4 cm. in front of the posterior 
end; c, about 6 cm. from the posterior end. 
3.—Inner surface of the anterior portion of the mantle; 
I, attachment of the foot; 2, line of attachment 
of the dorsal integument to the mantle; 3, the 
dorsal blood sinus. 
4.—Pallial complex seen from the inner side, X 2. I, 
rectum; 2, renal aperture; 3, ventricle; 4, auricle; 
5, kidney; 6, pericardium. 
5.—Longitudinal section of the ventricle. 
6.—Longitudinal section of proboscis, diagrammatic. 
7-—Longitudinal section of the radular portion of the 
proboscis (a litcle to the side of the middle line); 
1, wall of proboscis sheath; 2, 3, radula; 4, radula 
sac; 5, salivary duct. 
