Medusae and Ctenophora 7n 



H . cirratus is represented in the collection by twelve specimens, two in 

 excellent condition, 13 and 14 mm. high, respectively; the others fragmentary, 

 from Collinson point, Camden bay, north coast of Alaska, September 15 to 

 October 14, 1913 (stations 276 to 286), under the sea-ice. 



This material adds little, except in the way of confirmation, to Hartlaub's 

 account of large series. But inasmuch as the species has not been recorded 

 previously from American waters, a figure and a brief statement of the most 

 diagnostic features are given here. 



The general form of the bell is, itself, characteristic, there being, as Hartlaub 

 has pointed out, a thick rqunded apical gelatinous projection, with shallow bell 

 cavity (PI. I, fig. 2), this agreeing with Catablema vesicaria, which Hali- 

 tholus much resembles in its general appearance, but from which it is easily 

 separable by such important structural characters as absence of mesenteries 

 and structure of the, gonads. 



In the better preserved specimens there are, respectively, thirty-five and 

 thirty-six large tentacles, and in each a few rudinentary ones in the various 

 stages of development. 



The shape of the tentacles, with laterally flattened basal bulbs, is much as 

 described by Hartlaub. All specimens show the low, broad, peduncle, which 

 is one of the characteristics of this genus, and the four much crenulated lips 

 (PL I, fig. 3; Hartlaub, 1913). The primarily horseshoe-shaped gonads, with 

 transverse folds directed toward the perradii (PI. I, fig. 3) recall his figure, as 

 well as the related genus Leuckartiara (Maas, 1904). 



But, while this gonad-type is fundamentally characteristic, the surface 

 plications of the gonads cannot always be relied on as a systematic character; 

 for while in one of the specimens it is well exemplified, in the other, an adult 

 female, the entire interradial zones of the gastric wall are so packed with large 

 eggs, easily visible even with the hand lens, that the genital folds are obscured. 



There are no diverticula from the margins of the canals, either radial or 

 circular; but the edges of the former are slightly wavy (Hartlaub, 1913). 



There are no ocelli. 



The only Medusae with which H. cirratus is likely to be confused are 

 Catablema vesicaria and the species of Leuckartiara and Neoturris. But from 

 the first of these it is easily distinguished by the lack of mesenteries, by the 

 smooth- walled canals, and especially by the structure of the gonads; from 

 Leuckartiara by the absence of mesenteries and ocelli; from Neoturris by lack 

 of mesenteries and structure of gonads. 



H. cirratus has previously been recorded, as listed by Hartlaub, 

 from various localities in the Baltic, Barents sea and Spitzbergen (for list 

 of localities see Hartlaub, 1913, p. 274). 



The present captures show that it actually has a circumpolar distribution. 

 But its occurrence as far south as Kiel bay shows that it is not distinctively 

 arctic in its occurrence, but may be expected as far south as Cape Cod on the 

 eastern, as well as in Bering sea on the western coast of America. 



Colour: An excellent coloured sketch, from life, by Mr. Frits Johansen, of 

 the specimen from station 27u, shows the manubrium of a deep pinkish violet, 

 tentacles pale pink. 



Family BYTHOTIARID^ Maas. 



Eumedusa similis, gen. nov., sp. nov. 

 PI. I, Figs. 4, 5; PI. II, Figs. 1, 2. 



One specimen, 13 mm. high by 10 mm. broad (type); station 27v, off 

 Collinson point, Alaska, October 7, 1913; surface temperature, 30 F. ; ice, 10 

 inches thick. Catalogue No. 26, Victoria Memorial Museum, Ottawa. 



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