54 HALICORXAPwIA 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 pinnaB arise somewhat from the anterior 

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

 ridges. 



There are usually three 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 nnd 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 nematophores. (Figs. 3, 6.) 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. 5) the phylactogonia as well as the gonangia fire 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. 

 PL XXXIV. 



Troj/hosomc. — Stem strong, attaining a height of about five inches, 

 sini})le, monosiphonic pinnate almost to the base ; internodes of stem 

 each giving off two pinnae, 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. Hydrotheca^ wide; 



* Tlu' jiiMius Halicnrnaria fouiidcd by HlI^k, wlu) usod it in a widiT sonso, is lioro inti'Uilod to iiudiidc 

 only tliosi' I'luniulaiidii' wliicli, with a trophosomc formed on the general t\\^ of Aghiophenia, have gonan- 

 gia which arc ni'vcr iui hided in eoibnla; or protected hy phylactogonia. 



