64 AMERICAN HY DRUIDS. 



THUIARIA ELEGANS Kirchenpauer. 



(Plate VII, fig. 4.) 

 Thuiaria elegrms KIRCHEXPAUER, Nordische Gattungen und Arten, 1884, p. 21. 



Trophosome. Colony attaining the height of about 4 inches. Stem slender, slightly flexuose 

 with irregularly disposed deep annular nodes, beset on all sides with the stumps of broken 

 branches. Branches inserted on all sides of stem, flexuose, divided by deep nodes into long inter- 

 nodes. Hydrothecas alternate, oval, entirely immersed; aperture obliquely cut so as to form 

 two angles to the otherwise horizontal margin, the outer angle or projection being much larger 

 than the inner (adcauline), so much so that it (the outer tooth) forms a backward directed horn. 



Gonosome. Unknown. 



Distribution. Plover Bay, Bering Sea (Krause). 



I have not seen this species, and have taken the above description from the original by 

 Kirchenpauer, the translation being modified to accord with the plan of description followed in 

 this work. 



Type. In the Lcipsic Museum? 



THUIARIA ROBUSTA Clark. 

 (Plate VIII, figs. 5-7.) 



Thuiaria robusta CLARK, Proc. Acad. Nat. Sci., Philadelphia, 1876, p. 227. 

 Thuiaria rubustu KIRCHENPAUER, Nordische Gattungen und Arten, 1884, p. 81. 



Trophosome. Colony consisting of a simple stem attaining a height of about 12 inches 

 in the largest specimen examined. Stem strong, flexuose, bearing stumps of spirally arranged 

 branches throughout about three-fourths of its length, the upper portion bearing large branches 

 which bear branchlets arranged in a spiral so that the distal part of a colony assumes the shape 

 of a dense brush or tuft. The main stem and branches give off a branch to each internode, while 

 the hydrocladial internodes are of varying length, each usually bearing a number of subalternate, 

 thickly approximated hydrothecse. Hvdrothecaj long, tubular, slightly swollen below, immersed 

 to the aperture on larger branches, but with distal one-third exserted on distal part of branchlets; 

 aperture bilabiate, operculum with two flaps on distal portions of branches, often with round 

 margin and single abcauline Hap on proximal portions. At the base of each hydrotheca is a 

 thickening of the perisarc described by Clark as a double-pointed pyramid (see fig. ;">). 



Gonosome. Gonansjia borne in rows on the terminal branchlets, slender, with a terminal 



O 



collar and aperture, and two long curved spines rising from the antero-lateral corners of the 

 shoulders. 



Distribution. Sea Horse Islands and Cape Prince of Wales, Arctic Ocean; Haguieister 

 Island, and 12 miles east of Kings Island, Bering Sea (Clark). Arctic cruise of Corwin, 

 1885. Albatross* Station 2ST5, lat. N. 48 30', long. W. 124 57', 40 fathoms; Station 3153, lat. 

 N. 37 57' 10", long. W. 122 56' 20", 32 fathoms; Station 3504, lat. N. 56- 57', long. W. 169 : 27', 

 34 fathoms; Station 3505, lat. N. 57 09', long. AV. Ids ' 17', 44 fathoms; Station 3511, lat. N. 

 57 C 32', long. W. 169 38', 3D fathoms; Station 3515, lat. N. 59 59', long. W. 167 53', 13 fathoms; 

 Station 3540, lat. N. 56 27', long. W. 166 08', 51 fathoms. 



This species is not nearly so rigid us T. thuja, and the gonosome is entirely different. 



Type. In the collection of the U. S. National Museum. 



THUIARIA THUIARIOIDES (Clark). 



(Plate VIII, figs. 1-6.) 

 Sertulnrin tlniinrioides CLARK, Alaskan Hydroids, 1876, p. 223. 



lluiinfniili-s CALKINS, Some Hydroids from Puget Sound, 1899, p. 361. 

 Tliiiinriii tliiijiii-iniili'x II \KTLAUB, Hydroiden aus dem Stilleu Ocean, 1901, p. 354. 



tlniiiii-iiiiili'x NUTTING, Hydroids of the Harriman Expedition, 1901, p. 186. 



'. Colony attaining a height of about 7i inches. Main stem irregularly 

 branched, the branches being inserted in a spiral owing to the twisting of the stem; internodes 



