HYDROZOA. 
6VL 14 
in fresh water, but will recover entirely, more or less speedily, when 
restored to sea water after having been exposed 6-10 minutes to fresh 
water. Brine acts as an anaesthetic, &c. 
Htdrozoa and Craspedotb Medusae. 
Ilydractinia arhorescens, sp. n., Carter, Ann. N. H. (5) i. p. 298, 
pi. xvii, figs. 1-4, on shells, Polynesia?, Philippines? (also Palaeonto- 
graphica, xxv. 3, p. 109, pi. xii. figs. 1 & 2). 
Co[r]r^^««, g. n., Mereschkowsky [Zool. Rec. xiv. CteZ. p. 15]. “Hydro- 
rhiza a continuous layer, consisting of a mass of anastomosing tubes, cover- 
ing the shells of Gastropods ; from its surface rise spines and sexual and 
nutritive individuals ; trophosome cylindrical, with a single whorl of fili- 
form tentacles ; the sporosacs rise directly from the hydrorhiza, without 
the intervention of blastostyles.” 0. horealis^ sp. n., id. (17 a), p. 327, 
pi. XV. figs. 7-11, on shells of Fusus and Buccinum^ White Sea, 
10 fath. 
Blastothela, g. n., Verrill (allied to Myriothela and Acaulis). “ Body 
elongated, sessile, attached at base by slender, simple, root-like processes ; 
a circle of slender tentacles near the base ; above these are many stout, 
single processes (blastostyles), which bear the small sexual zooids (gono- 
phores) on their sides ; upper portion of body elongated, covered with 
small capitate tentacles.” B. rosea^ sp. n., id. Am. J. Sci. (3) xvi. p. 374, 
New England, 7-20 fath. 
The craspedote Medusm from Heligoland described and figured by 
Bohra (4) are : Clytia johnstoni. Aid., p. 167, pi. ii. figs. 1-9 ; Campanulina 
acuminata^ Aid., p. 171, pi. ii. figs. 10-14 ; Ohelia geniculata^ L. ?, p. 174, 
pi. iii. figs. 1-34 ; Tima pellucida. Will., p. 181 ; T. sp., p. 182, pi. iii. 
figs. 35 & 36 ; Tiaropsis scotica, Alim. ?, p. 183, pi. ii. figs. 15-30 ; Lizzia 
octo -punctata, Sars, p. 186, pis. iv. v. & vi. figs. 1-4 ; L. hlondina, Forb., 
p. 168, pi. vi. fig. 5; Bougainmllia ramose, van Ben., p. 189, pi. vi. fig. 6 ; 
Syncoryne {Sarsia') eximia, Alim., p. 191, pi. vi. figs. 7-26, pi. vii. figs. 1-6 ; 
Tiara pileata, Forsk., p. 194 ; Hyhocodon prolifer, Ag., p. 195, pi. vii- 
figs. 7-9 ; Ectopleura dumortieri, p. 198, pi. vii. figs. 10-13. An elaborate 
synonymy is given in each instance. 
{Incertm sedis.) Claus (9) has examined the structure of Tetrapteron 
(Tetraplatia) volitans, a curious, minute, quadrilateral Coelenterate orga- 
nism, swimming about by means of four small lateral lobes, which are re- 
tractile into niches, and are provided with two otolithigerous sense-organs 
on their lower surface. Its organization proves it to belong to the hydro- 
zoon rather than to the anthozoon type ; though it has been hitherto 
observed only in the immature state, Claus is not inclined to regard it as 
a larval form. Infcertain respects, its arctitectonic suggests the Charyb- 
deidm. Observed at Messina. 
Leptoscyphus grigoriewi, sp. n., Mereschkowsky (17 a), p. 239, pi. xiv. 
figs. 1 & 2, upon Ascidice, White Sea, 6 fath ; medusa of Ohelia flahellata^ 
ibid. p. 253, pi. xiii. fig. 7. 
Sertularia compressa, sp. n., id. (17 D), p. 446, pi. xvii. figs. 17-19, North 
Pacific. 
