HYDROIDS OP BEAUFORT, NORTH CAROLINA. 



373 



Gonosome. — A single gonophore is borne on the front of the stem just at the base. The gonan- 

 gium is large, nearly oval, but broader at the distal end than at the proximal, provided with five 

 or six broad corrugations; apertiu'e large, circular, occupying all, 

 or nearly all, of the distal end. An operculum is stretched tightly 

 across the aperture. 



Distribution. — Found abundantly on floating sargassum, off 

 Bogue Bank. 



In his paper mentioned in the synonymy, Hargitt gives a full 

 description of a species of Pasythcawhich he calls P. nodosa, imder 

 the impression that it is different from P. quadridentata. My speci- 

 mens would answer his description exactly, but I believe they 

 belong to the species P. quadridentaia. I have foimd numerous 

 gonangia and they agree exactly with those of that species. This 

 resemblance is really the determining factor, and I think if Hargitt 

 had found gonangia on his specimens he would have come to the 

 same conclusion. I have compared my specimens with Nutting's 

 types, and I find that the stem supporting thegroupsof hydrothecae 

 is much shorter and stouter in mine than in his, but the gono- 

 some is exactly similar. Furthermore, I find that mine agrees 

 perfectly with the figures given by Bale, in both of his papers, 

 and he foimd his gonangia agreeing with those of P. quadri- 

 dentaia. 



Fig. 36. — Pasythea quadridentata (Ellis and 

 Solander). A, portion of colony; B and 

 C, gonangia. 



Genus SERTULARELLA. 



Trophosome. — Stems and branches usually divided into distinct intemodes; hydrothecjE alternate; 

 margin commonly with three or four teeth; operculum with three or four flaps. 

 Gonosome. — Gonangia large, often annulated. 



Sertularella conica All man. 



Sertularella cotiiea Allman. Hydroids of the Gulf Stream, 1877. p. 21. Clarke, 

 Bull. Mus. Comp, Zool.. 1879. p. 246. Nutting, American Hydroids, pt. n, 

 1904, p. 79. Fraser, West Coast Hydroids, 1911, p. 68. 



Trophosome. — Colony attaining a height of 20 mm. in Beaufort 

 specimens, but reported elsewhere as high as 45 mm.; unbranchcd, 

 or sparsely or irregularly branched; stem divided into regular inter- 

 nodes by oblique nodes, slanting upward to the one side and to the 

 other alternately; liydrothcca; free for about two-thirds of their 

 length, swollen proximally and narrowing distally; shallow corruga- 

 tions present; margin provided ^\ith four rather acute teeth and a 

 four-flapped operculutn, the four flaps meeting to form a cone-shaped 

 extremity for the hydrotheca. 



Gonosome. — Gonangia on vcrj- short pedicels grow directly from 

 the hydrorhiza, oval, corrugated; collar distinct, but little smaller 

 than the part of the hydrotheca on which it rests; margin with four 

 distinct teeth , less acu te than those on the margin of the hydrotheca. 

 Apparently the gonophores are produced while the colony is still 

 young, as in the same specimens in which they were present there 

 were stems with only one hydrotheca, some with two and none with more than three or fotu". 

 Distribution. — On sponge dredged by the Fish Hawk. 



No gonosome was found in these specimens. The description and the drawing have been made 

 from specimens obtained from Vancouver Island and reported in the paper referred to in the synonymy. 



Fig, 37, — Sertularella conica Allman. 

 portion of colony; B', gonosome. 



A, 



