16 



Planar ia sabauriculata . 



ing beyond the foot, neither is it jointed : bristles retractile, 

 strong, jointed near the top, the point fixed on in a bayonet 

 fashion; they are collected into two small unequal fascicles 

 having a rather small spine in the middle of each : anal seg- 

 ment truncate and terminated with two long tentacular cirri. 

 This little worm is occasionally met with in Berwick Bay, 

 lurking at the roots of Conferva?, corallines, and sponges, be- 

 tween tide marks. It advances through the water with con- 

 siderable velocity, and in a wriggling manner, pushing out 

 and alternately withdrawing the bristles of its feet, and mov- 

 ing its long cirri in every direction. When the creature is 

 active and first taken, the cirri have a somewhat moniliform 

 appearance under the microscope, but as its activity declines 

 this appearance becomes fainter : they then appear only 

 jointed like a common Conferva, and after death even these 

 joints disappear, and the whole organ assumes a homogeneous 

 structure. 



52. Plana'ria subauricula v ta. {Jig. 2.) 



The animal, when fully extended, is about six lines long, 

 and two broad, obtuse in front and tapered behind ; thus as- 

 suming a lanceolate, 2 

 or tongue-shaped, 

 figure, very thin, 

 flat, smooth, and of 

 a pale or wood-brown 

 colour, with some 

 milk white spots scat- 

 tered over the back. 

 Towards the anterior 

 end we perceive nu- 

 merous Small black Uf Pianaria subauriculata of the natural size ; b, the same 

 eveS 01' SDecks Col- magnified, the dorsal aspect ; c, the ventral aspect. 



lected into two irregular parcels with a transparent space 

 between them: the eyes themselves are placed about and 

 within a small circular transparent spot on each side, which 

 is changeable in appearance, and has sometimes the look of 

 a small fold, or auricle, as is represented in figure b. The 

 body is transparent enough to allow us to perceive that there 

 are no defined organs, or vessels, beyond the proboscis, which 

 is situated about the middle, and opens on the ventral sur- 

 face : the interior appears to be entirely composed of gela- 

 tinous globules, separated into compartments by clear lines, 

 which run from the centre to the pellucid margin in an im- 

 perfectly radiating manner. 



