x 



Leptotilum gracile, varietas norvegicum, nob. 



Tab. XIII. 



Specific Character. 



The polypidom is ioo mm. long and 0.630 mm. broad, rather slender, and flexible. The upper extremity slightly 

 dilated; the lower part terminating in an oblong bulbus, 0.550 mm. broad. The rachis, 70 mm. in length and 0.280 mm. in 

 breadth, bears 50 fully developed polyps, and between these a multitude of non-developed; along the lowermost part of the 

 rachis 2 series of non-developed polyps, 10 in each. 



The ventral surface round and naked. The dorsal surface round, having on either side a series of alternately dis- 

 posed polyps, with very prominently developed cells. 



The polyp-cells calyx-shaped, 6 mm, long and 1.5 mm. broad at the base; 2 mm. at their upper margin, which has 

 8 pyramidally formed points, consisting of long calcareous needles. The cells abounding in calcareous needles. 



The polyps somewhat longer than the cells. The tentacles in the middle of the aboral surface furnished 

 with a longitudinal series of spicules, measuring 0.068 mm. in length. The body of the polyp and the oesophagus without 

 calcareous deposit. 



The sarcosoma of the polypidom beset all over with calcareous needles similar to those in the cells; they are from 

 0.196 mm. to 0.205 mm. in length. 



The axis round and flexible, 0.136 mm. broad, extending from the upper extremity of the polypidom to about 1 mm. 

 from the bottom of the bulbus. 



Colour of the sarcosoma and the polyp-cells perfectly hyaline. The polyps, with their tentacles, yellowish-white 

 and pellucid. The oesophagus a dark madderbrown. 



