REPOET ON THE HYDROIDA. 
25 
internode, and tlie extreme rim of the hydrotheca is surrounded by a narrow band of a 
colour somewhat lighter than that of the rest of the w T alls. The main stem has a 
thickness which is about twice that of the ramuli, and is divided into internodes, each 
carrying a hydrotheca on alternate sides exactly as in the ramuli. 
The ramuli are given off from the main stem, each close to the point from which the 
peduncle of a hydrotheca springs. In the more proximal portion of the stem they all 
lie in one and the same plane with the hydrothecae, but towards the distal parts they 
frequently, immediately after their origin, take different directions, and have thus, though 
all simply distichous at their origin, the appearance of being irregularly scattered. 
Thyroscyphus simplex, n. sp. (PI. XIII. figs. 1, 2). 
Trophosome. — Colony attaining a height of nearly six inches ; stems monosiphonic, 
clustered unbranched, and carrying along nearly their entire height pinnately disposed 
alternate ramuli. Hydrothecae borne both by main stem and ramuli, deep, cylindrical, 
terminating below in a short unjointed peduncle, which is supported directly on the 
summit of a stout lateral process of the internode. 
Gonosome not known. 
Locality. — Off Somerset, Cape York, Torres Strait; depth, 8 to 12 fathoms. 
Thyroscyphus simplex occurs in clusters of three or four erect simple stems which 
spring from a common creeping tubular fibre, and are regularly set throughout with 
alternate pinnae, wdiich towards the middle of the stems attain a length of nearly an 
inch. Every internode of stem and pinnae carries close to its distal end, and on alternate 
sides, a short lateral process which directly supports the short peduncle of the hydrotheca. 
The hydrotheca at its base loses its exactly symmetrical outline and becomes slightly 
gibbous on the side which is turned towards the internode, and here an oblique 
diaphragm forms the boundary between its cavity and that of the peduncle. The four 
valves with "which the hydrotheca is crowned are very thin and membranous, and form 
when in apposition a beautiful pyramidal roof. There is no marginal band. 
In habit and general physiognomy Thyroscyphus simplex so closely resembles 
Gompanularia insignis that a careful examination is needed in order to distinguish 
the two forms. 
Hypanthea, Allman. 
Hypantliea, Allman, Report on the Collections made by the Transit of Venus Expedition to 
Kerguelen Island, Phil. Trans., 1879, vol. clxviii. p. 281. 
Generic Character. Trophosome. — Hydrothecse borne each on the summit of a 
cylindrical peduncle, which springs from a creeping stolon, inoperculate, with the 
(zool. chall. exp. — part lxx. — 1888.) Aaaa 4 
