116 AMKRK'AN HYDKOIDS. 



sometimes vorv irregularly so. often divided into internodes each of which boars two hydrothecao, 

 but in other cases with no nodes at all, unless the constriction of the base be regarded :is such. 

 Hydrothecse exceedingly variable, those in typical specimens collected by Dr. Dall are vorv short 

 and stout, subalternate, swollen below, rapidly constricting throughout their free distal third, 

 and ending in a smooth circular margin and aperture directed upward and outward. There is 

 often a sharp constriction or indentation just below the margin on the adcauline side. The 

 operculum could not bo seen in specimens examined, hut is doubtless present in fresh specimens 

 and consists of one adcauline flap. All intergradations occur between the hydrotheca above 

 described and one much more slender with distal one-half free and aperture horizontal. 



OonOKo/ne. Gonangia ovate, small, borne on upper sides of branches, with a largo distal 

 aperture and a row of chitinous points some distance below the aperture. Another form described 

 by Clark is pyriform instead of ovate. 



I>ixtr/lniti<iii. Abundant on Alaskan coasts, Aleutian Islands, Boring Sea, San Miguel Island, 

 California (Dall); Allmtr<i Station 2S57, hit. X. 5s 05', long. W. 15<> 4>', 51 fathoms; Station 

 2St>4, hit. N. 4s L'2', long. W. li 51', 4s fathoms; Station 2sr>fi, hit. N. 4s <>!'. long. W. 

 125" 03'. 171 fathoms; Station 28SI1, hit. N. 4: J . 5'.)', long. W. 124 50' 30", :.o fathoms; Station 

 3231, hit. N. 58 35', long. W. 157 2s' 5(1", 12 fathoms; Station :-;4C,5. hit. X. 4s -21', long. W. 

 123 14', 4S fathoms; Station 359!t, hit. N. 52 : 05', long. E. 177 40', 55 fathoms; Puget Sound 

 (Nutting). 



This is one of the most variable species known, and it is fortunate that Dr. Dall secured a 

 large series showing the intergradations between the extreme forms. The species ranges from 

 shallow water to a depth of 171 fathoms. 



'////". In the collection of the U. S. National Museum. 



ABIETINARIA INCONSTANS (Clark). 



(Plate XXXIII, %s. 1-1'.) 



fii'i-tiiliii-in uii-aiiKlans CLAKK, Alaskan Hydmids, ISTii, ]>. 1'L'l'. 

 Aliii'Hiiiirin . iiiriiiixiinix KIRCHENPABKR, Nordische Gattungen, lss4, p. :>ii. 



TropJwsome. Colony attaining a height of about 1 inch in specimens examined. Stem verv 

 stirt and course, dark colored, divided into numerous sharply separated internodes on proximal 

 unbranched portion; branched portion divided into regular intornodos by oblique nodes; inter- 

 nodes each hearing a branch and two hydrothecse on one side and a single hydrothoc-a on the other. 

 Branches erect, almost parallel with main stem, forming a dense tuft, alternate, basal portion 

 marked by several sharp annulated constrictions, internodes short usually bearing one or two 

 pairs of hydrothec.e. Ilydrotheeie very similar to those of A. p'limln, but much heavier and 

 coarser, although not attaining anything like the size of ^1. ultii'tinn^ swollen below, the distal 

 third free, narrowing' to a circular margin beneath the adcauline side of which is a constriction 

 and thickening of the hydrothecal wall; aperture facing upward. Sometimes there is a chitinous 

 tooth projecting inward from the adcauline margin. Operculum not seen, but doubtless of the 

 regular Abietwarna pattern. 



(iiniiixiuiie. "The gonangia show the greatest amount of variation of any species that 1 know 

 of; it is impossible to describe their form, for there is not one of them that seems to agree with 

 anv other." 1 "Sessile, large, orifice terminal, small, discoidal: outline vorv irro<ndar. taporiii"' 



r^ ^ . rt I 1~> 



usually at the base; borne in two rows on distal portion of main stem." The present writer has 

 not seen the gonangia. 



DixtrUnititni. Unalaska beach (Dall). This species can readily be distinguished from its 

 nearest ally, A. jil!<-iilii, by its thick, dark stems, and very deep annulations and nodes, as well 

 as by the heavier and denser hydrothecse and ascending branches. 



T///H. -In the collection of the I'. S. National Museum. 



H'lark. Alaskan Ilydrnids, IsTli, p. 21':!. 



