526 Mr. J. Ritchie on new Hydroida Thecata 



the liydrothccae. They are ovate in shape, with a bul<>inpj 

 shoulder, a short neck, and a circular aperture. The distal 

 half is ornamented with prominent scattered spines. 



Loc. Andaman Islands. Collected by J. Wood- Mason. 



Plumularidae. 



Aglaophenia septata, sp. n. 



Tropho'^ome. — Stem fascicled and unbranched, 74 ram. 

 high. The hydroclades are borne on the anterior tube of the 

 fascicle, which alone is divided by faint nodes into regular 

 internodes. The hydroclades are biserial, lie on the anterior 

 surface of the stem, from which they project at an angle of 

 40°-45°, and reach a maximum of 11 mm. in length, llegu- 

 larly placed nodes occur on the hydroclades, the internodes 

 ])eing divided by numerous strongly developed septa, four of 

 Avhich project from the posterior wall of the hydrotheca, 

 while three arise from the anterior wall of the internode 

 proximal to the hydrotheca. Of these one traverses the base 

 of the mesial sarcotheca. 



The hydrothccai are rather distant, very narrow at the 

 base, but widening greatl}- towards the top, almost obconical. 

 The anterior profile is straight but for a concavity opposite 

 the top of the mesial sarcotheca. The margin is horizontal 

 and has a prominent anterior tooth, flanked on each side by 

 four distinct sinuations. There is no intrathecal ridge, but 

 the posterior wall bends inwards just above the base of the 

 hydrotheca. The suj^racalycine sarcothecae slightly overtop 

 the margin of the hydrotheca. They are large and cylin- 

 drical and possess an internal septum. The mesial sarco- 

 theca is about two-fifths the length of the hydrotheca, to 

 ■which it is altogether adnate except for a free spout-like tip. 

 A button of chitin projects into its cavity from the wall of 

 the hydrotheca, proximal to the point where it becomes free. 



Of cauline sarcothecse, one lies on the anterior of the 

 stem, proximal to the hydroclade- bearing process, anotiier lies 

 on the inner side of the process — both of tiiese being large 

 and similar to the mesial sarcotheca, — while a third, a mere 

 perforation, lies on the anterior of the process itself. 



Gonosome. — A kind of corbula, entangled amongst fibres 

 at the base o£ the colony, I assume to have belonged to tiie 

 colony. It is of peculiar type. A cylinder, formed of delicate 

 plates of chitin, contains five spherical reproductive bodies, 

 and along each side run two rows of projecting leaves. 

 Each of the lower rows contains about 9 tube-like leaves. 



