1903.] MEDUSA FROM BRITISH COLUMBIA AND ALASKA. 171 



well-marked unbranclied lateral diverticula. These diverticula are 

 absent on the upper margin of the circular canal, and are thus 

 unlike the condition described in Catahlema by Haeckel. 



Colour.— EqW bluish throughout ; tentacles, gonads, and stomach 

 dark red or purplish. 



Habitat.— ^t. Paul Island, Pribyloff Islands, collected by 

 Kincaid. 



Discussion. — The large number of tentacles in double rows and 

 the opposite position of the diverticula of the stomach, bearing 

 gonads, are the reasons for placing this form under Ttorris. It is 

 true that the stomach and gonads are small for Tiorris, but the size 

 of these organs is variable. Beyond these considerations this form 

 seems to resemble more Tiara pileata than any species of Tunns. 

 It differs from Turris digitalis in the smaller apical process, the 

 size of the gonads, the shape of the radial canals, and the length 

 of the manubrium ; from T. neglecta in the shape of the stomach 

 which is not cubical, in the regular opposition of gonad-pouches, 

 and in the number of tentacles. The specific characters are : — 

 the short conical apex, the large number of tentacles (140), 

 arranged in two rows, the spindle-shaped radial canals having 

 simple lateral diverticula throughout their length, the five or more 

 pairs of gonadial pouches from each of the four stomach-lobes, the 

 small size of these and the stomach ; in these respects it approaches 

 the condition in Tiara, and, lastly, in its size. Tihrris digitalis, 

 the original Medusa digitals of Fabricius, is remarkable for its 

 extensive distribution in northern waters ; it is probable that 

 Turris neglecta will be found to have a similar distribution. Four 

 out of the seven genera of Haeckel's subfamily Pandseidte have 

 been reported from arctic waters. 



III. Margelid^ Haeckel. 

 HipPOCRENE Mortens. 



1. HiPPOCRENE MERTENSii (Haockel, 18, p. 92). 



Synonym Bougainvillia mertensii Agassiz. 



Specific desanjytion.—The bell is nearly spherical, somewhat 

 flattened, and contracted at its four meridional points, having 

 thus a cubical appearance, 5 mm. by 4 mm. The velum is well 

 developed. The oral tentacles are situated at the upper end of 

 the proboscis — two large, one small, and one rudimentary : this 

 last being due possibly to imperfect preservation or an abnor- 

 mality of the specimen. There is a marked inequality of the 

 tentacles and the tentacle-bulbs. The former are stout, branched 

 at the base, each branch dividing dichotomously about six times. 

 Two of the tentacle-bulbs are large, horseshoe- shaped, and twice 

 as broad as the proboscis. Each bears twenty-one tentacles 

 and as many eye-spots. The other tentacle-biilbs could not be 



