HYDROIDS OF BEAUFORT, NORTH CAROLINA. 

 Family PE.\NARID.€. 



355 



Trophosome. — Colony branched ; hydranths with a proximal whorl of long filiform tentacles around 

 the body of the hydranth and several capitate tentacles on the proboscis, these usually in a series of 

 whorls. 



Gonosome. — Gonophores producing free medusse with four radial canals and four rudimentary 



tentacles. 



Genus PENNARU. 



Trophosome.— Colony large, much branched, often with a distinct pinnate or twice pinnate arrange- 

 ment; hydranth with a large proboscis, very noticeable when extended, well supplied with whorls of 

 capitate tentacles. 



Gonosome . — Gonophores borne on the hydranth 

 body just distal to the proximal whorl of tentacles; 

 medusEe very large, often mature, when liberated. 

 They may even liberate the sex products before 

 being set free from the hydranth. 



Pennaria tiarella McCrady. 



Pennarta tiarella McCrady. Gymnoph. of Charleston 

 Har., i8s7, p. SI. Hareitt. American Naturalist, 



1900, p. 387. Hargitt, American Naturalist, 1901, p. 

 311. Nutting. Hydroids of the Woods Hole Region, 



1901, p. 337. 

 Trophosome. — Colony large, sometimes reach- 

 ing the height of 6 inches; branching twice pin- 

 nate. A varying number of annulations, never very 

 many , occur on the main stem above the origin of the 

 branch and on the branches above their origin. 

 The hydranths are large, narrowing distinctly to 

 form the proboscis. There are 10 or 12 filiform 

 tentacles and a varj-ing number of capitate tenta- 

 cles which are usually arranged in four or five 

 quite regular whorls in the fully developed hy- 

 dranth. Often a hydranth bud appears growing 

 directly from the wall of the main stem or branch. 



Gonosome. — Gonophores few in number; when there are more than one on a hydranth at the same 

 time they seldom are at the same stage of development. The medusse are oval or ovate; rudimentarj' 

 tentacles, radial canals, and the manubrium with its gonads are all well developed, and the sexual 

 products may be dehisced before the medusa; are set free. 



Color. — Stem and main branches of dark horn color; hydranths and medusa markings similar to 

 each other in color; they may be a vermilion or pink or they may be a light gray, almost a white; ten- 

 tacles white. 



Distribution.— On the crab float and the piles of the United States Bureau of Fisheries wharf, on the 

 piles of the railway bridge at all points from Morehead City to Beaufort, on stones and shells in shallow 

 water in many near-by localities. 



Hargitt, in his 1900 paper, speaks of two varieties of this species as it is found at Woods Hole: The 

 one occurring early in the season, a deeper form with little tendency to bilateralism, with little colora- 

 tion in hydroid or medusa, the medusa being inactive or never becoming free; and a shallow water or 

 smface form, occurring later, which is distinctly bilateral, with higher coloration in hydranth and 

 medusa, the medusa being active, the whole colony having a more rapid growth than the former. He 



FlO. 13.— Pennaria tiarella McCrady. A. hydranth and gono- 

 some; B, bud growing directly from the branch. 



