10() LAND AND i'KESHWATEU 



and liver-lobes (7) (ii^». 2a, 2/'), the albumen-glaiid, hermaphrodite- 

 glands, and duct. Through the diaphragm and attached to it, and 

 lying on the right-hand side, pass the intestine behind and the 

 genitalia in front, a short distance the one from the other. 



The ])rincipal retractor muscles have their attachments on 

 the roof of the main body-cavity, which is represented viewed 

 from below in figs. 2 c and 2 b, from the right side in tig. 2 a. 

 The largest and strongest is that of the buccal mass ; it occupies 

 a central position, the point of attachment being close to where the 

 uterus and oviduct pass through the diaphragm into the visceral 

 chamber, and on the strong muscular diagonal division of that 

 chamber. The retractor muscle of the left eye-tentacle is given off 

 from it lower down, while that of the right eye-tentacle is a bi- 

 furcation in a similar way with that of the penis retractor. The 

 attachment of this is also central and immediately behind the buccal 

 retractor. About the middle of its length, the buccal retractor 

 muscle is attached to the upper surface of the stomach (fig. 2g), 

 a beautiful adaptation, allox^ing this and the salivary glands to 

 retain their relative position with the movements of the animal. 

 Another set of muscles of the buccal mass have their attachments 

 on the side or dorsal position. Two of these, which I name the right 

 and left dorsal muscles of the buccal mass, have their attachment 

 points forward on the diaphragm, and one central dorsal muscle on 

 the integument of the neck ; and one is on the left side of the 

 diaphragm opposite its perforation by the intestine (fig. 2 b). The 

 retractor muscle of the dart (D) holds the most posterior position of 

 all, centrally at the back of the body-cavity. One long and three 

 shorter very strong muscles are attached to the lower floor of 

 the body-cavity (Bp, fig. 2d) and are connected with the under- 

 side of the buccal mass. On the side of the foot some short isolated 

 muscles are attached to the same floor and in connection with 

 the nervous ganglia. All form a most beautifully balanced and 

 constructed system of nervous tendons, pulling and contracting 

 one against the other in every direction. There are many other 

 minor sets closer to the buccal mass or attached to the sides and floor 

 of the body-cavity, and some that are attached to the amatorial 

 organ {vide Plate LXXXV. figs. G, 6). 



The intestine (i) on entering the visceral cavity (fig. 2 /'), en- 

 folded by the liver-lobes, occupies the posterior portion. The albumen- 

 gland (AJ.gd) is situated close to its entrance, the hermaphrodite- 

 duct running backward to the extreme hinder part of the cavity, 

 the herma]jhrodite-glauds being embedded in the liver-lobe which 

 occupies this position also. The intestine forms a reversed S-like 

 loop forward, returns backward, then expands into a globose form, 

 and contracting again forward passes to the anus. The pulmonary 

 cavity is forward, in direct and short connection with the respiratory 

 orifice : the auricle and ventricle are also in this forward position, 

 the renal organ of oval form being above it. Above all the thin 

 membranaceous long spatulate shell covers the integument of the 

 visceral mass. 



