100 Mr. D’Arcy W. Thompson on new Hydroid 
ville Thomson for his kindness in permitting me to describe 
the present collection, and to Prof. Allman and Mr. Busk 
for much kindly given and highly valued assistance. 
Sertularella neglecta, sp. nov. (PL XVI. fig. 1.) 
Trophosome. Idydrocaulus attaining a height of about f of 
an inch. Pinnm alternate, rather irregular. Hydrothecaj 
long, tubular, gracefully curved, a very small portion only 
immersed 5 all directed somewhat towards one side of the 
stem ; one, rather shorter than the rest, in the axil of each 
pinna; orifice triangular, with three long pointed teeth. 
Colour reddish brown. 
Gonosome. Gonangia obovate, with close, strongly-marked 
transverse wrinkles,* and a distinct and longish neck-orifice 
with two rounded teeth. 
Locality. Australia (probably Bass’s Straits) (Dr. Harvey). 
My specimens of this species are all much shrivelled, so 
much so as to make the exact form of hydrothecae and go¬ 
nangia not easily ascertained. My figure, however, is, as far 
as I can judge, fairly accurate. 
Sertularella fruticosa. (PI. XVI. figs. 2, 2 a.) 
Sertvlaria fruticosa, Esper, Hist, des Zoophytes, suppl. 
Sertularia laxa, Lamarck, Hist, des Anim. sans Vertebres, vol. ii. 
p. 116 . 
Trophosome. Hydrorhiza dense, fibrous, and matted. Hy- 
drocaulus attaining a height of about 12 inches, strong, coarse, 
and woody. Pinnae long, alternate, arranged at wide inter¬ 
vals. Hydrothecae large, cup-shaped, distant, often almost 
subpedicellate ; orifice wide, unconstricted, margin entire. 
Gonosome. Gonangia arising from the pinnae, just below the 
base of a hydrotheca; small, not much larger than the hydro¬ 
thecae ; obovate, smooth, margin entire, operculate (?). 
Locality. New Zealand (Dr. JoUijfe). 
This species is a most striking and conspicuous one, from 
the great size both of the hydrothecae and of the whole zoo¬ 
phyte ; and it is a matter, therefore, of some wonderment to me 
to find no mention of it in recent authors. 
In general appearance it closely resembles Campanularia 
juncea , a form from Ceylon figured by Prof. Allman in the 
Journ. of the Linnean Society, vol. xii. ; indeed the generic 
relations of both species are somewhat uncertain. 
The capsules are singularly small for so large and robust a 
species. In one or two I think I can detect traces of an 
operculum ; but they are too much shrivelled for such a 
structure to have been fully preserved. 
