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GENUS V. GREGORIA (Gosse). 



Base not broader than the column. 



Column a low pillar, strongly invected, very in- 

 flatable in irregular lobes; the margin forming an 

 irregularly undulate parapet, separated from the ten- 

 tacles by a deep but narrow fosse, which is never 

 obliterated. Surface smooth, but becoming trans- 

 versely wrinkled in contraction ; without suckers ; 

 perforated with few, but very conspicuous loop-holes ; 

 these are arranged in longitudinal lines, on the swell- 

 ings, which correspond to the intersepts. Substance 

 pulpy. 



Disk plane; not exceeding the column; smooth, 

 without conspicuous radii. 



Tentacles moderately short, blunt, unicolorous ; not 

 perfectly retractile. 



Mouth set on a cone ; lip thin ; two gonidial grooves, 

 each with a pair of small tubercles. 



Aconlia emitted sparsely. 



