124 AMERICAN HYDKOIDS. 



HYDRALLMANIA Hincks (modified). 



Trojih'ixHiiit'. Hvdrotheea.- in groups all on one .side of the branches, their bases aligned and 

 closely approximated, their distal ends lient alternately to the right and left. Operculum 

 apparently of a single adcauline flap. 



Go>ift//ii: Gonangia oblong-ovoid, without lateral spines or marsupium; aperture large, 

 round. 



This is a perfectly well marked genus, consisting of a few species that agree in the 

 peculiar position of the hvdrotheca' and in the special character of the alternate flexing of their 

 distal ends to right and left when viewed from the front. The only species known at the time 

 preceding Ilincks's great work had bc-en for a long time placed in the genus Plumulceria hy many 

 authors. The absence of the sarcosiyle was sufficient to differentiate it from the family 

 Plumularidse, and other characters served to settle its affinities with the Sertularidse. 



Since the genus was instituted by Hincks in ISfiiS 1 it has been recognized by practically 

 every writer that has discussed it or had occasion to mention the type species. Mr. Paarmann. 

 who carefully investigated the opercula of this and other Sertularichv, found that the operculum 

 consists of a single functional adcauline flap, and that the margin was produced into a stationary 

 "collar" on the adcauline side. 



KEY To THE A.MEKICAX SI'ECIKS OF THE fiEXI'S H YIIKALI.M ANI A. 



Hydrothec;e distinctly flask shaped, distal ends much constricted, aperture round 



Hydrothec;e more nearly tubular, distal ends not distinctly constricted and not round. 



Each hydrotheca in a group reaching above the middle of the one next above it 



Each hydrotheca in a group not attaining the level of the middle of the next one above - 



HYDRALLMANIA FALCATA | Linnaeus). 



(Plate XXXVIII, tigs. 1-4.) 



,sVr/./< <;,i-nlliin- EM. is, Essay Nat. Hist. Corallines, 1755, p. 12. 



l^i'i-lnlnriii Jnli-ntii bixs.Ki's, Systema Xatunr, 175s. p. SIO. 



Sertularia slipulata I.INX.KI s, Systema Natune, 175s, p. ,si.'!. 



Si'i-liilni-iii f<ilr<il Lixx.i'.rs, Systema Natune, 17H1, p. 541. 



Sn-liiliiriii J'lilmln Horrrrvx, Natuurlyke Historic, XVII, I7K1-177:;, p. 546. 



Sertularia falciitii P.U.I. AS, Klenchus Zoophytoruni, 17I>(>, ]>. 144. 



Si-rliilnriii Jnlriiln LiXN.Kfs, Systema Xatunr. ll'th ed., 17117, ]i. 13011. 



Serliiliii-in fiilriiln BODDAKUT (I'allasi, Lyst der I'lant-Dieren, 17HS, p. ISO. 



Si-fliilin-'ni Jiili-iiln MAHATTI, I>e I'lantis /oophylis, 177(i, p. .SO. 



Serlularia falcata GRoyovivs, Zoophylacium gronovianum, 17.SI, p. .'15!i. 



Xi'i-iiiluriii J'lili-nln EI.I.IS and SOI.AXDKH, Nat. Hist, /ooph., 17SH, p. 42. 



Si-i-liiliii-iii jii/i-iilii Wn.Kixsand HEUIJST (Pallas), Charukteristik der Thier]iHan/.en, I7S7, ]i. 183. 



X,;-iiil,ii-iiij'ti/i'<ilii <;.MEMX, Systema Xatnni', Kith ed., 17SS, p. 3849. 



Plumularia falcata KSPKR, Die Prlanxenthiei'e in Abhildungen, III, 17SS-ls:;o, p. 1'24. 



Si'i-titliii-iii J'lilriitu HEKKEXMOCT, Synoi>s. Nat. Hist. Great Britain, I, 17SSI, p. 217. 



Sertularia falcala Esriou, Fortsetzungen der Pflanzenthiere, II, 17!M-|soii, pi. n. 



SiTtiiliiriiiJ'iili-iilii I'.osc. Hist. mil. des Vers, III, ISIIL', p. !>5. 



Sertularia falcatu TI-I:TON, British l-'auiui, IS07, p. 213. 



Sertularia fnlcala 3 \ME&oy, Cat. . \nirn. Class Venues, isll, p. 5ti4. 



J'l'iiiini-iii (Sertularia) fitlcata (>KKX, Lelirbuch der Naturgesrhichte, 1S15, p. !I4. 



Pliiiiiiilurin jnlriilH L\M\KIK, Hist. nat. des aniiii. sans Vert., ISlli, p. 125. 



Ayln<t/ilit -ilia full-ill, i l.sMornorx, Hist. nat. des, Polypiers, ISKi, p. 174. 



S,'i-lii/tii-iti j'li/rnlii STE\V urr, Elements Nat. Hist. Aniin. Ivingd., II, 1S17, p. 44.S. 



,S'i i-lnliii-iii fiili-iilii SCIMVEKIGER, Handbuch der Natnrgescliiehte, 1S20, ]i. 427. 



r/Hiiiii/'ii-i'i j'llrntti FI.EMIM,, British Animals, 1S2S, p. 54(i. 



Si-rtiiliirin Jnlnilii BOM, Hist. nat. des Vers, KSliO, p. Mil. 



riiniiiiliiriiij'iili-iilii JOHNSTON, Trans. Newcastle Society, II, 1S32, p. 25!i. 



Pliiiiniliiriii fiilriiln i IK T'.I.AIXVII.I.H, Manuel d' Ac-tinoldgie, is:!4, ]i. 477. 



'British Ilydroid Zociphytes, Isiis, p. 27M. 



