ivith Observations on Australian Hydroids. 9^ 



a single series of small sarcothecse. Each has a hydrotheca 

 projecting from it near the base, these hydrothec^e con- 

 stituting the " single branches" mentioned by Mr. Busk. 



In the " Challenger" Report the branches of this species 

 are described as being bifariously disposed on the stem;. 

 but this is an oversight, as, indeed, is made apparent by the 

 fiofure, which shows them as given off in several different 

 directions. Their disposition is very regular, and perfectly 

 uniform in the specimens which I have seen from two 

 different localities. The main stem is distinctly flexuous, 

 and from each angle springs a branch. The branches, how- 

 ever, are not in the same plane, but are arranged spirally 

 round the stem, so that every four branches form a complete 

 whorl, there being thus three longitudinal series up the stem, 



Aglaophenia phoenicea, Busk. 



I have no doubt that the Lytocarpus spectahilis of the- 

 " Challenger" Report is identical with the type form of 

 Aglao'phenia {Lytocarpus) phoenicea, though the form 

 figured in the Report is of stronger and coarser habit than 

 any of my specimens. Professor Allman gives a figure of 

 the gonangial pinna, or nematocladium^ which agrees in 

 essential points with the same part in a Port Darwin speci- 

 men, the only one which I have found fertile. The first 

 internode bears a hydrotheca^ the next a gonangium, and 

 the remainder of the pinna is armed with sarcothecge, and 

 recurved over the rachis. As Professor Allman points out, 

 the gonangium springs from an elevation of the internode^ 

 which has two lateral saicothecee on the distal side of it^ 

 and a median one in front. This elevation evidently repre- 

 sents a hydrotheca, to which it bears a considerable resem- 

 blance when seen in front view after the gonangium has been 

 removed, the point of attachment representing the aperture 

 of the hydrotheca. A peculiarity presents itself in my 

 specimen which is not shown in Professor Allman's figure — 

 namely, that the first sarcotheca above the gonangial inter- 

 node, which is on the proximal side of the nematocladium, 

 is unpaired, the space opposite it on the distal side heing 

 vacant, while all the other sarcothecaB to the end of the 

 pinna are in pairs opposite each other.* 



* Several species of Aglaophenia, with open corbul®, have the first and 

 second sarcothecse on the nematocladia unpaired, but in these the vacancies. 

 are on the proximal side — A. divaricata, A. 'plumosa, &c. 



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