472 PROFESSOR G. J. AILMAN OX THE HTDROIDA 



few other gymnoblastic species were collected. These belong apparently to the genera 

 Eudendrium and Perigonhmis ; but the state of preservation of the specimens is not 

 such as to render it possible to determine them more closely. 



Descriptions op New Species. 

 LAFOiilD^. 

 Lafoea halecioides. Plate LXVI. figs. 1, 1". 



Trophosonie. — Stem attaining a height of about two inches, pinnately branched, rigid, 

 branches alternate, main stem and primary branches fascicled ; ultimate ramuli jointed 

 at irregular intervals, not fascicled. Hydrothecee shortly pedunculate and disposed mth 

 a regularly pinnate and alternate arrangement along the length of the ultimate ramuli, 

 and along that of the principal branches, one almost always situated in the axil of each 

 ultimate ramulus ; deeply cyathiform, with the axis slightly curved, and with the margin 

 even, and slightly everted, usually marked for some distance below the margin by 

 faint circular striae. 



Gonosome not known. 



The present species has a very rigid habit, and possesses much of the aspect of certain 

 Haleciums. It approaches Lafoea fridicosa by its large size and shrubby growth, but 

 differs from it by its pinnate ramification and HaleciuniASke habit. As in every other 

 species of Lafoea hitherto described, no gonosome was present. 



It was dredged from the cold area at depths of 640 and 345 fathoms, the temperature 

 in both cases having been ascertained to stand at 30° Fahr. 



THUIAEID^. 



Thuiabia laxa. Plate LXV. figs. 1, 1°. 



Trophosome. — Stem attaining a height of about nine inches, and furnished with 

 fan-shaped groups of dichotomous branches for some distance fi'om the distal extremity, 

 while it is destitute of branches for the greater part of its course ; groups of branches 

 about an inch in length, flexile, arched, with the convexity of the curve looking upwards, 

 arranged spirally, rather distant, each branchlet of every bifurcation having a joint at 

 its base, and having for the most part one or more joints at irregular distances along 

 its length ; stem gently zig-zag, annulated at the base, and with groups of two or three 

 annuli at intervals for some distance upwards, gi^ing the appearance of joints. Hydro- 

 thecae scattered upon the main stem, but on the branches alternate, each separated from 

 those above and below it by a space equalling about one fourth of its own height ; orifice 

 transversely elliptical, provided with a valve-like operculum. 



Gonosome. — Gonangia piriform, springing from the upper side of the branches, each 

 in an interval between two neighbouring hydrothecae of a series. 



