132 AMERICAN HYDROIDS. 



opposite sides. Branches alternate, borne on short, thick processes from the stem, sometimes 

 unbranehed, often dividing once and occasionally bearing regularly alternate branches, as does 

 the stem; nodes very distant or absent. Hydrothecffi tubular, arranged in four rows on proximal 

 parts of branches and in six (rarely eight) rows on distal parts, closely approximated, entirely 

 immersed, narrowing toward the distal curved portion and ending in a smooth toothless margin 

 and oval aperture; operculmn a single abcauline valve. The number of rows on a branch is 

 suddenly increased from four to six by the intercalation of two new rows between the old ones. 



(fdiKixuii'ii'. Unknown. 



I>ix1rilni1idii. Port Moller. Alaska; llagmeister Island. Bering Sea; Chirikott' Island, 

 Chiachi Islands (Clark), Puget Sound (Calkins). Bristol Bay, Alaska (collected by C. L. McKay), 

 Arctic Ocean (Murdoch). Depth ranging from the shore line to IT fathoms. 



This appears to be a well-marked species, about which there has been little difference of 

 opinion. It is the one most abundant on the North Pacific coast. 



Ti/j>f. In the collection of the I'. S. National Museum. 



SELAGINOPSIS OBSOLETA (Lepechin). 



(Plate XXXIX, li-rs. 4, :< XL, liir. 4. ) 

 ,S', iiii/iii-iii nlisolei'i LEI-ECHIX, Arta Acini. IVtrnpol.. 11, 177S, 1't. 1', p. 1M7. 



,Si i-liilin-iii nliKiilelii (iMEi.ix, Systrma Xatnni- I LimiM-nsl , I7SX-I71G, p. .'!S4li. 

 ,\rlnl,n-i<i ,iliK,il,-l<i !'.< isc, Hist. Nat. iles Yrrs, ISO:!, p. 93. 

 Xei-liiliiriii ulixiililn LAMIHKOCX, Hist. Pulvp. Cnrallii.'riies, islti, |.. 197. 

 Polyserias glacialis MEKESCHKOWSKY, Ann. anil Ma;.'.. 1th scr. , XX, 1S77, ]i. L'28. 

 Pdli/xi'riim hint-/.-.*!! MKUKsniKim'sKY, Ann. iunl Maj;., "ith SIT., I, 1S7S, p. :;:;7. 

 >SWm/i/'"/'- s '' s liii/i'kxii MEKESCHKOWSKY, Ann. ami Alaj;., ."itli SIT., II, 1S7X, p. 444. 

 Si'liii/iiiii/ixix uliiaih'tii KiifciiExi'Ai-EK, .Niinlisrlie (iattuii'.'cn, ISS4, p. 10. 



Trophosome.GfAony attaining a height of about i inches. Stem thick, slightly geniculate, 

 divided into irregular internodes, the tendency being toward an arrangement in which there are 

 two branches to an interuode, with an occasional very deeply cut node, particularly on the distal 

 portion, and also very shallow annulations that are much more numerous than the real nodes. 

 Branches alternate, closely approximated, springing from short processes from the stem from 

 which they are separated by very deep nodes; otherwise the nodes are almost entirely absent. 

 Hydrotheca- arranged in six regular series so that they form both vertical rows and spirals, 

 tubular, rather short, broader at the base, and narrowing distally to the smooth margin and oval 

 aperture; there are no marginal teeth, and the operculum is composed of a single abcauline Hap. 



There is usually a distinct space intervening between the top of one hydrotheca and the 

 bottom of the one immediately above it. 



"Gonophores in a young state in the form of a reversed cone, just as in /'. in!i'<il>!l!x, but 

 generally smaller. In the adult state thev retain their conical form, but the cone becomes larger 

 and more elongated; below, it is attached by a short peduncle; above, it is truncate, with the 

 margins much rounded, and furnished with a tube of very inconsiderable length, which is 

 scarcely observable, and much narrower than in the preceding 1 species. The gonothecie of this 

 species are never present in such abundance as in /'. m!i'l>/lix." 



D!xtr!liul!i>>i. Polar Sea (Lepechin); White Sea (Mereschkowsky) ; St. Pauls Island. Bering 

 Sea, 23 to 25 fathoms (A. and A. Krause): .l/iW/v.v Station :-'..">o.s, hit. N. 5s :::-!', long. YV. 

 164 49', :>:', fathoms. 



Kirehenpauer, who had access to the type specimens of .V. nlxul, f,i in the Leipsic Museum, 

 declares that the A'. />///</ .,-// of Mereschkowsky is a svnonvm of this species. 



Not having the material upon which to base a decision, the pre.-ent writer adopts the position 

 taken by Kirehenpauer, as that writer had the advantage of studying Lepechin's type. The 

 above description of the gonosome is quoted entire from Mereschkowsky. 1 



'////"' In Leipsic Museum. 



'Annals anil Magazine of Natural History, ."itli scr., I, ls7s, p. ;;:!,. 



