52 " ENDEAVOUR " SCIENTIFIC RESULTS. 



each side, everted almost horizontally, and another lobe, more 

 rounded, adjoining each lateral sarcotheea ; back entire, adnate : 

 the aperture into the hydroeladium with a few minute denticles 

 on the margin. No septal ridges in the internode. 



Mesial sarcothecse about two-thirds the length of the 

 hydrothecse, projecting free portion short, but with the terminal 

 and lateral apertures generally distinct ; terminal aperture very 

 small, circular, rarely replaced by two still smaller, side by side. 

 Lateral sarcothecse adnate, saccate, with one or two tubular 

 apertures, one directed downwards at right angles with the 

 hydrotheca, the other, when present, directed upwards and for- 

 wards, but commonly merged completely in the wide lateral 

 aperture. Cauline sarcotheca? similar to the laterals, two on the 

 rachis at the base of each hydrocladinm, and a third at the back 

 of each axil. 



Gonotheca? about three times the length of the hydrothecre, 

 campanulate, truncate. " Ses vessies, courtes nrceolees et 

 nomhreuses, sont sessiles sur le rachis, entre les pinnules " 

 (Lamarck). 



Colour. — Light fawn, stems darker. 



The description and figures of H. urceolifera given by Billard 

 sufficiently resemble these specimens to permit of their reference 

 to Lamarck's species, though the type specimen seems to be a 

 larger form (25 centimetres in height), and there are some minor 

 differences. The hydrotheca; are broader, in front view, than 

 those of any other species known to me. A very characteristic 

 feature, in side view, is the abrupt bending-in of that portion of 

 the hydrotheca which includes the anterior tooth, while the two 

 teeth next to it remain erect. The front view is no less distinc- 

 tive, the three teeth referred to appearing in that aspect as 

 nearly equal and very near together, contrasting strongly with 

 the nearly allied species. H. prolifera and others, which in 

 front view show the median tooth standing alone, with the first 

 pair of laterals sloping outwards and comparatively distant. The 

 median tooth is not thickened nor crested, but merely a lobe of 

 the hydrotheca-wall. The lateral sarcotheca 1 much resemble 

 those of H. ascidioides, but the free front margin is often cut 

 back so far as to obliterate the upper circular aperture. In 

 those near the ends of the hydrocladia the lower aperture becomes 

 gradually more distinctly tubular, and directed more forward. 

 The mesial sarcothecse have the terminal and lateral apertures 

 generally distinct, a rather exceptional condition when the 

 apertures are so closely approximated as in this species. The 

 single circular terminal aperture seemed at first to mark a dis- 



