70 AMERICAN HYDROIDS. 



THUIARIA TUBULIFORMIS ( Marktanner-Turneretscher) 



(Plate XI, figs. 1-8.) 

 I>>/ii<iiin'iiii iiiliiiliforn/ix MARKTANNER-TURNERETSCHEH, Hydroiden dt-.s k. k. natnrhist. Hot'mnseums, 1890, p. 238. 



T/'fij>?it.w>u'. Colony growing in tufts of straight steins, reaching a height of about 3 

 inches. Stein straight and even throughout, divided into regular internodes, each of which bears 

 a branch and two hydrotheca.' on one side and a single hydrotheca on the other. Branches strictly 

 alternate, divided into irregular internodes and much constricted at their origins. Hydrotheca' 

 subopposite, long, tubular, with the greater part of their lateral outline parallel to the branch, 

 the upper portion being abruptly bent outward and ending in two large opposite teeth and a 

 two-valved operculum. 



<7nii<ii>iiii-. (fonangia growing on front of stem, large, ovate, with a constricted curved 

 neck and round terminal aperture. 



I>i>itril}iiti<in. Dschidda (Dr. Billitzer); Bay of Balm, Brazil (Rathbun); Florida, between 

 Salt Pond and Stock Island (Dr. E. Palmer); Bahama Banks, :-} to <i fathoms (Nutting). 



The gonosome of this species is figured here for the first time. There is a slight tendency 

 for the hydrothecie to arrange themselves in groups, reminding one of those, found in the genus 

 i* the upper ones in each group being somewhat smaller than the lower pair. 

 C. In the k. k. Hofmuseums, Vienna. 



THUIARIA TENERA (Bars). 

 (Plate XI, figs. 9-12.) 



Sertularin Inn-i-n SAHS, P>idrag til Kundskaben om Norges Hydroider, 1873, ]i. 20. 



Sertulnriii ti'inni HIXCKS, Ann. and Mat:., 4th SIT., XIII, pp. 129 and 151. 



Sei-tul,,,'!,! Inifm WIXTHER, Xaturhist. Tidsskrift (3), XII, 1879-SO, p. 24ii. 



Hi-1-tnltiriti li iii'i-ii LEVINSEX, Vid. Udb. "Hauclis" Togter, 1893, p. 384. 



Kirliilin-iii ti'iin-ii MAKKTAXXEK-TCRXERETSCHER, Hydroiden des k. k. naturhist. Hnfmuseuins, 1890, p. 230. 



Sertuiaria /.//</ LEVIXSEX, Vid. Meddel. naturhist. Foren., 1892, p. 4S. 



KeHiiltiriii leneni MARKTANXER-TURXERETSCITER, Ilydroiden von Ost Spitzbergen, 18113, p. 418. 



,^1-rli/Iiii-in feiii-i-H XFTTIM;, Hyilmids frnni Alaska and Pu-iL't Sounil, 1899, p. 743. 



Tlniiin-iii li'iii'i-n P.OXXEVIE, North Atlantic Expedition, 1899, p. 83. 



Tlniiiifin leiK'i'ii S.EMI-XDSSON, Bid rag til Kundsk. islandske Hydroider, 1902, p. (12. 



Tropko&ome. Colony attaining a height of about 3 inches in largest specimens examined. 

 Main stem straight proximally and slightly tlexuose distally, divided into long and irregular 

 internodes bearing strictly alternate branches and three hydrotheca' (one axillary and two not) 

 between adjacent branches on each side. Branches usually undivided and with rather short 

 internodes, which often bear a single pair of hydrotheca'. Hydrotheca' subalternate, flask- 

 shaped, rather slender, widely separated, much exserted, with a tubular distal portion; margin 

 varying greatly, sometimes being round and without teeth, and often being curved, with two 



/ n B / 7 n & 



teeth of regular sertularian type'. In many cases the margin is produced into a thin collapsible 

 tube. Operculum usually composed of one flap attached to ahcaulinc side of margin, but 

 sometimes composed of two flaps. 



Go//t>tto///(\ (ionangia ovate, with a round terminal aperture and a short collar. 



I>!nfi'i}>i<f!i>n Kodiak Island and Bering Straits (Dall); Allxitrnux Station i'SC>5, hit. N. 

 48 12', long. W. l-2-l 4!i', 4u fathoms; St. Pauls Island (Nutting); Norway, 159 fathoms (Sars); 

 Iceland (Hincks); Denmark (Winther); Christiania (Marktanner-Turneretscher); Spitsbergen 

 (Marktanner-Turneretscher); North Atlantic (Bonnevie). 



This sjiecies appears to break down the generic distinctions proposed by Levinsen in that it 

 has both a one-flapped and a two-flapped operculum in the same specimen. 



