220 



to a phase considerably in advance of the well-known locomo- 

 tive gemmules of the marine bryozoa. 



Dr. Allman also made some observations on the Anatomy 

 of Polycera quadrilineata. 



In this moUusk the buccal mass is furnished with two pow- 

 erful corneous jaws, acted on by distinct muscles, and con- 

 tains a spinous tongue of very complex structure. The (Eso- 

 phagus leads to a stomach, which is imbedded in the anterior 

 extremity of the liver, and from which an intestine first passes 

 forward and then curves backwards, to terminate at the anal 

 outlet, which is situated between the two posterior leaflets of 

 the bronchial tuft. Two pair of glands are connected with 

 the buccal mass. The liver, though in its natural condition 

 it is compact, like that of Doris and its allies, may yet be 

 unravelled so as to display its minute structure ; and it is then 

 seen to consist essentially of a ramified tube, whose branches 

 end in slightly dilated cuts de sac, and are furnished along 

 their sides with closely-set spheroidal divertacula, which 

 would seem to be the essential secreting portion of the organ. 



The heart consists of an auricle and ventricle, and occu- 

 pies the back of the animal immediately in front of the bran- 

 chial tuft ; it is furnished with auriculo-ventricular and aortic 

 valves. 



The brain consists of six supra-oesophageal ganglia, and 

 the nervous collar is completed below by a band of nervous 

 matter, which passes from the most external ganglion of one 

 side, round the ventral aspect of the oesophagus, to the corres- 

 ponding ganglion of the other side ; the nerves which supply 

 the dorsal laminated tentacula are furnished at their base with 

 large ganglionic dilations ; and two small pharyngeal ganglia 

 are placed upon the ventral aspect of the oesophagus just as 

 this tube leaves the buccal mass. 



The eyes are almost sessile upon the anterior ganglia of 



