HYDKolUS OF THK WOODS HO I/I-. Kl.OIO'N. 



Diphasia fallax (Johnston). Fig. ">S. 

 (SertulaHa/allaxlolspaton, British Zoophytes, 8th edition, p. 127.) 



Ti-oiiliiimiiiit'. CuKiiiy branched, the terminal brandies often abruptly curved so as to form a hoo k 

 or short coil. Hydrothec;e stout, with a wide, sinuous margin dosed liy an operculum hinged to it 8 

 inner .side. 



Uimoxinnf. Female gonangia with four leaf-like cxi)ansions above; male gonangia with four 

 terminal spines. 



h'lxlriliution. Shallow water, often grow- 

 ing on other hydroids. A specimen found in 

 the U. S. Fish Commission collection at Woods 

 Hole is labeled "K. by S., Sankety, Nantucket, 

 23 fathoms, V. N. E." Off Watch Hill, 17 to 

 21 fathoms. (Verrill. ) 



Diphasia rosacea (Linn.). Fig. 59. 

 (Kertuluria rusncin Linn., Syst. Nut., 130U. ) 



Tfojiliiixamt'. Colony branched; branches 

 more slender than in D. ful/a.r, and more widely 

 separated. Hydrothecu 1 delicate, transparent, 

 slender, tubular, abruptly bent outward near 

 the middle; aperture facing nearly upward, 

 sinuous, dosed with an internal operculum con- 

 sisting of a single piece. 



ti'iiiiiiisome. Female gonangium pyriform, 

 longitudinally ridged, with two prominent 

 pointed processes on top, and a round internal 

 marsnpium; male gonangium "pyriform, curved 

 toward the base, traversed* by longitudinal 

 lamellated ridges, which rise above into spi- 

 nous processes around a slender tubular orifice." 

 (Hincks.) 



Distribution. Fisher Island Sound, 9 to 11 

 fathoms. ( Verrill. ) 



SERTULAEELLA. 



Ti-iijthoxouif. Colony usually branching; stem and branches divided into regular internodes, 

 each bearing one or two hydrothecsc. Hydrothecie strictly alternate, borne on opposite sides of th e 

 branch, usually with toothed margins provided with an operculum consisting of more than one piece. 



diniomme. (ionangia as in Sertularia, but usually more or less annulated. 



Kdj to ipeciesofSertufaretta found in Hie Woods Hole region. 



A. Hydrothecal margin without teeth or operculum 

 A'. Hyrtrothecal margin with three teeth 

 A 1 . Hydrothceal margin with 4 teeth. 



a. Teeth obscure. Hydrothcea fusiform, deeply annulated orwrinkled tnmsversply S. rugosa. 



a'. Hydrotheese very large, sometimes corrugated above. Branches approximate S.gayi. 



a". Hydrothoccc medium-sized, smooth. Branches irregular and distent , S. trirurpidata. 



Sertularella abietina (Linn.). Fig. 60. 



Trophonome. Colony pinnately branched; branches thick and coarse, approximate, divided into 

 internodes, each of which bears one or two hydrothecso; nodes oblique. Hydrothecse large, alternate, 

 bulging below and narrowing above to a tubular neck with a round, even aperture without an 

 operculum. 



59. Dipliatia rosacea 

 (Linn.). 



' *.v i 'lnl<ir in nliirfiiia Linn., Syst. Nat., p. 1307. 



