280 Rev. Mr. Berkeley on the 



curved over the oesophagus ; its surface with a groove down the center, 

 and armed with regularly disposed bristly points, as in the Pectinibranchia. 

 The salivary glands take their origin on the back of the oesophagus, al- 

 most immediately after it leaves the mass of the mouth : at the point of 

 their origin they are united, and from thence ascend on each side for a 

 short distance obliquely, but soon are curved downwards, and again up- 

 wards, when, by means of a slightly flexuous attenuated canal, they pass 

 beneath the former portion of them into the mass of the mouth, on each 

 side of the oesophagus. 



At this point is the nervous collar surrounding the oesophagus ; on each 

 side of which is the cerebral ganglion : on the right side the lateral gang- 

 lion is approximated to the cerebral ganglion, but on the left side it is si- 

 tuated beneath the oesophagus. From the right lateral ganglion a nervous 

 cord passes above the tongue and oesophagus, and forms a ganglion at the 

 point where it meets the lateral surface of the cavity of the neck ; from 

 the left ganglion a nervous cord passes beneath the tongue and oesophagus, 

 and forms a ganglion on the opposite side. 



The oesophagus runs laterally into a linear oblong sac, which is obtuse 

 at one end, and confluent with the intestine at the other. This sac, when 

 accurately examined, is found to be of a very curious structure. Out- 

 wardly it appears to consist of two distinct sacs, of which the lowest is 

 nearly elliptic, broader and more muscular, with a constriction at the 

 very top ; and above this an irregular elongated sac, which has towards 

 the base two constrictions, and above the first constriction, on the left, a 

 few longitudinal striae are discernible, pointing out, as it should seem, the 

 situation of a small pouch. 



The whole is, however, pervious, and the appearance above stated is 

 caused by a muscuhr process, which takes its course through the whole 

 length of the sac. When the sac is opened, and its* contents carefully 

 removed, the lower portion is found to be furnished with a thickened 

 raised muscular rib, which follows the outer or sinistral margin of the 



* When the animal has been kept without food for some time, and killed by 

 immersion in scalding water, the sac is filled with a somewhat flesh-coloured 

 substance, of a firmish consistence, which, if carefully removed, is a perfect 

 cast of the interior of the sac. 



