4 PROCEEDINGS OF THE NATIONAL MUSEUM vol.75 



BEAK SCULPTURE 



Plate 1, fig. 5 J 



ALIMENTARY SYSTEM . 1 



Plate 1, fig. 9 



The mouth is immediately below the anterior adductor muscle. 

 It is oval in shape and leads by a short gullet into the stomach, which 

 is of irregular shape, but more oval than globular, with plications on 

 its inner surface, and lies just posterior to the anterior adductor 

 muscle. Surrounding the stomach are the digestive glands, hepato- 

 pancreas, a brown, spongy mass made up of minute tubes in clusters 

 whose orifices open into the stomach. The intestme is given off from 

 the left posterior portion of the stomach and, in alcoholic specimens, 

 is about 3 mm. in diameter. It descends obliquely through the 

 visceral mass with a slight curve almost to the posterior margin of 

 the foot where it curves dorsally following the line of the foot margin- 

 It is narrowest here, about 1 mm. in diameter. At a point midway 

 between the dorsal and ventral portions of the body mass the curve 

 proceeds anteriorly and continues in an oblique line until at a point 

 below the anterior portion of the renal organ it turns to the right 

 and then backward, still following the curve of the foot, and contin- 

 ues anteriorly for about two-thirds of the length of the body where 

 it is attached to the visceral mass. Turning again to the right side 

 of the body, it continues dorsally and posteriorly, keeping to the right 

 of the portion descending from the stomach. It continues anteriorly 

 for a short distance where it again turns and passing upward becomes 

 very broad — about 5 mm. in diameter. From this point the wall is 

 produced into a fold (typhlosole) continuing through the rectum. 

 Approaching the dorsal surface in an oblique line it grows gradually 

 smaller until it turns abruptly backward and passes into the pericar- 

 dium; leaving the visceral mass, the intestine or rectum passes 

 through the heart over the posterior adductor muscle, and bending 

 dorsally terminates with the anus in the suprabranchial chamber. 



The labial palps and alimentary system are the same for all species. 



NERVOUS SYSTEM 



Plate 1, fig. 10 



Paired nerve centers or ganglia, with their emanating branches and 

 commissural cords connecting the ganglia, form the nervous system. 

 There are three nerve centers, an anterior, a visceral, and a posterior, 

 supplying the respective portions of the body, which are called the 

 cerebral ganglia, the pedal ganglia, and the posterior ganglia. 



The cerebral [ganglia are paired and lie bilaterally symmetrically 

 on each side]pf the^body in front of the protractor pedis muscle. 



