HYDROIDS OP BEAUFORT, NORTH CAROLINA. 

 Genus AGLAOPHENIA. 



377 



Trophosome. — Hydrothecal margin provided with sharp teeth; posterior intrathecal ridge present; 

 one mesial and two supracalycine nematophores for each hydrotheca always present. 



Gonosome. — Gonangia inclosed in true corbulae, formed of modified pinnae. There are no hydro- 

 thecae at the bases of the gonangial leaves. 



Key to the Species op Aglaophenia Found in the Beaufort Region. 



A. Colonies branched. 



a. Branching regularly pinnate or twice-pinnate A. acacia. 



b. Branching irregular, branches coming off singly or in pairs from the anterior of the stem. 



A, rigida. 



B. Colonies unbranched A. minuta. 



Aglaophenia acacia Allman. 



Aglaophenia acacia Allman, Challenger Report, pt. -xx. Hydroida, 1883. p. 38. 



Trophosome. — Colony reaching a height of 6 inches. There arc no branches on the proximal portion 

 of the stem, but distally they are given off regularly, in opposite or subopposite pairs. These branches 



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Fig. 



-Aglaophenia acacia Aihnstn. A, portion of hydrocladium: B. hydrotheca. side view, more highlymagnified; C. hydro 

 theca, front view, more highly magnified; D. corbula (after .\llman). 



may also give off branches in pairs to form a twice-pinnate arrangement. The whole colony has a 

 much more spreading appearance and is much more graceful than .4 . rigida. The intemodcs of the main 

 stem arc not distinctly marked off, or at any rate not so distinctly as some other species; the h)'drocladial 

 shoulder is near the middle of each intemode. Each intemode has two nematophores, one above and one 

 below the shoulder. The hydrocladia are very regularly arranged, are all nearly the same length, from 5 

 to 8 mm., throughout the larger portion of the branch or branchlet, but gradually shorten toward the 

 distal end to produce a gracefully rounded effect. The hydrocladia arc divided into regular inter- 

 nodes, each of which has an internal ridge at the base of the supracalycine nematophore and one oppo- 

 site the intrathecal ridge. The hydrothecse are rather deep in comparison with their width. The 

 margin has about nine teeth, rather sharp and deeply cut. The intrathecal ridge is short but very 

 distinct. The supracalycine nematophores are stout, reaching to about the margin of the hydrotheca 

 or a little above it. The mesial nematophore reaches more than half way up the anterior wall of the 

 hydrotheca; the distal portion is free. 



Gonosome. — "Corbulse rather short and deep, with about six pairs of closely adnate costse." — 

 Allman. 



Distribution. — From fishing grounds outside of Beaufort Harbor. 



As there was no gonosome present, the description and the figure are taken from Allman 's paper. 



