54 HALICOItXAEIA SPECIOSA. 



The two strong teeth on the front margin of the hydrotheca are so 

 situated, that with the slightly everted intervening portion of the mar- 

 gin they give to this part the appearance of the lip of a jug, and con- 

 stitute a striking character. The pinnae arise somewhat from the anterior 

 aspect of the stem, and their internodes exhibit four well-marked septal 

 ridges. 



There are usually thi-ee or four male gonangia (Fig. 5) in a cluster, and 

 of these one is always placed in front of the axil between the stem of 

 the phylactogonium and its branch ; towards the distal end of the phy- 

 lactogonium the clusters are often reduced to a single gonangium. 



The branches of the female phylactogonium carry two longitudinal 

 series of large cup-shaped neraatophores. (Figs. 3, G.) These are situated 

 exactly opposite to one another, one on the front, the other on the back 

 of the branch, each series extending from the base to the apex of the 

 branch, and formed by about three equally distant nematophores. Along 

 the stem of the phylactogonium two series of similarly shaped nema- 

 tophores also occur. These are confined to the front of the stem, and 

 are disposed alternately. There is farther on the back of the phylacto- 

 gonium in each axil a somewhat bracket-shaped nematophore. (Fig. 4.) 



In the male (Fig. 6) the phylactogonia as well as the gonangia are much 

 smaller than in the female. Both stem and branches carry cup-shaped 

 nematophores as in the female, but in the male these are all confined 

 to the front. A bracket-shaped nematophore is carried on the back of 

 the phylactogonium over the axil of each branch, as in the female. 



Genus HALICORNARIA Busk (modified).* 



Halicornaria speciosa. 



PI. XXXIV. 



Trophosomc. — Stem strong, attaining a height of about five inches, 

 simple, monosiphonic pinnate almost to the base ; internodes of stem 

 each giving off two pinn*, which are opposite, or nearly so, towards 

 the base of the stem, but more alternately disposed towards the distal end, 

 where the internodes become longer and more oblique. Hydrotheca3 wide ; 



* The "'■enus Halicornaria fuuiuU'd liy Busk, who used it in a ividt-r sensu, is here intended to include 

 only those PlumularidiE which, with a trophosome formed on the general type of Aglaophenia, have gonan- 

 gia which are never imluded in corljidiv or proteeled by phylactogonia. 



