58 " ENDEAVOUR " SCIENTIFIC RESULTS. 



beyond it. In lateral view, being seen edge-wise, it appears 

 strictly linear, and is arched over the sarcopore in an almost 

 semi-circular form. Careful examination discloses the presence 

 of this structure in several of my other specimens, but there are 

 some iu which I have not succeeded in finding it. 



Apart from these peculiarities the hydrotheca differs con- 

 siderably from that of ordinary Statopleaus. Its rostrum is 

 formed, not, as is usual, by the anterior sarcotheca, but by a 

 prolongation of the hydrotheca itself, somewhat as in 

 Aijlaoplienia fonuosa (Busk). Here, however, the front of the 

 rostrum is closed in by a thin wall, which is continued down- 

 ward into the cavity of the hydrotheca, forming an anterior 

 intrathecal ridge, and terminating in a thickened margin. In 

 the first hydrotheca of each hydrocladium this rostrum is 

 commonly much reduced. Oil each side of the hydrotheca- 

 margiu there is a small rounded lobe, and running from the 

 intrathecal ridge to this lobe is a broad curvilinear baud, 

 distinguished from the rest of the hydrotheca by a difference in 

 thickness (the baud being apparently thinner). The back of 

 the hydrotheca is broadly sinuated. 



The anterior sarcotheca is short, and situated opposite the base 

 of the rostrum ; at first sight it would appear to originate from 

 the iiiternode and to run up the front of the hydrotheca, as in an 

 ordinary Aglaophenia ; closer observation, however, shows that 

 what might be taken for the proximal part of the sarcotheca is 

 really a process from the iuternode, not specially devoted to the 

 sarcotheca, but forming the channel of communication between 

 the cavity of the hydrocaulus and that of the hydrotheca, 

 which connect by means of a small opeuing into the hydrotheca 

 (the liydropore~) situated at the top of this process, Opposite 

 to this opening, and crowning the summit of the process, is the 

 sarcotheca, which is short, scoop-shaped, and entirely open on 

 the inner side. The position of the hydrotheca is similar to that 

 seen in some Plumularii.c (e.g. P. goldsteini), in which the 

 widening of the proximal end of the iuteruode, to embrace the 

 base of the hydrotheca, is carried to such an extent as to form a 

 distinct process, in the axil of which the hydrotheca is situated. 



The cauliue sarcotheca) are small and inconspicuous. There is 

 one on the rachis, just above the hydrocladium, another, often 

 very difficult to make out, on the base of the latter, while a third, 

 as Ritchie has pointed out, is found in the axil. 



The gonotheca?, Avhich are borne on the bases of the 

 hydrocladia, and are often turned alternately to left and right, 

 are somewhat irregularly ovate thick-walled capsules, showing 



