Gaity Marine Lahoratortj ^ St. Andreics. 53 



being somewhat shorter than in frout^ whilst beneath it is 

 a smaller lanceolate lobe. 



The inferior division consists of the three lobes (two 

 anterior and one posterior) and the ventral cirrus. The 

 compound bristles have the same structure. 



At the 60th foot a decided increase in the size of all these 

 flattened lobes is observable, especially in the inferior division, 

 and when the lOOtli foot is reached all may be called folia- 

 ceous. The lower dorsal far exceeds the upper in size. The 

 anterior lobes of the inferior division form thin but broadly 

 lanceolate flaps, whilst the posterior is as broad as both and 

 of an ovato-lanceolate outline. The ventral cirrus, again^ is 

 shorter than in front, but still broad and thin. 



At the change from the more rounded form to the flat- 

 tened condition of the body the whole of the processes of the 

 foot become enlarged and flattened. Thus the secondary 

 dorsal lobe in front of the superior tuft of bristles has become 

 a double flap wnth the bristles between. The two anterior 

 and the posterior lobes are also flattened out, whilst the 

 ventral lobe is proportionally less than in front. 



Posteriorly the feet diminish in size, but they retain a 

 similar character, the lobes, however, being much less, the 

 largest in jn'oportion being the dorsal (PI. IV. fig. 6, 90th 

 foot) . 



The example is a female laden with large ova. 

 In considering the relationship of this to the widely distri- 

 buted Goniada maculata two factors have to be weighed, viz. 

 the effects of environment in causing variation of the several 

 parts of the foot and the influence of sexual conditions. 



The addition of two lobes to the foot in the anterior region 

 of the body is perhaps the most marked divergence between 

 this and the ordinary type ; but as there is variability in the 

 latter on this head, too much reliance need not be placed 

 on it. 



There is less difficulty Avith the posterior feet, which diverge 

 from the ordinary form only by the foliaceous expansion of 

 the identical lobes of the feet, both dorsally and ventrally. 



Glycera capitata, ffirst., was dredged at Station 54, 1873, 

 off Prince Edward Island, from St. Jaques to Sea-Cow^ Head. 



Glycera siphonostojna, Delle Chiaje, occurred in 1872, 

 locality not stated. 



