25 
Halysites ortuopteroides, 1 sj). nov. 
(PL III, Figs. 1 and 2 ; PI. VII, Figs. 4 and 5.) 
Sp. Char . — Corallum massive, formed by large colonies, several inches 
in diameter, of parallel and non-radiate coral lites. Fenestrules large, 
polygonal, labyrinthine, curved, or generally irregular in form, with 
pronounced angles, or wholly rounded outlines; sizes 6x5 mm., 8x4 mm., 
10 x 5 mnn, 12 x 5 mm., 18 x 3 mm., 20 x 5 mm., and so on ; margins 
rather waved ; walls strongly corrugate. Corallites very long, tall (at least 
five inches, and then incomplete), parallel. Epitheca very regularly and 
coarsely striate. Corallite chains moderately farcimentiform, slightly 
undulating the margins of the fenestrules. Autopores large, long-oval, hut 
without square or truncate ends, lateral margins rounded, two to nine in each 
corallite chain, four being the average number, from one to one and a quarter 
millimetres in length by three-quarters to one millimetre in breadth ; visceral 
chambers transversely elongate (parallclogrammatic) ; tabuke complete, 
horizontal or concave, variable in their distance apart, hut usually half a 
millimetre. Gonopores very much larger than the mesopores, triangular, the 
sides either straight or concave, sometimes one of the angles truncate ; walls 
as thick as those of the mesopores ; visceral chambers nearly rectangular ; 
tabulae complete, horizontal, one-third millimetre apart. Mesopores trans- 
versely 2 3 elongate (parallelogrammatic), reduced to mere slits, or absent; 
visceral chambers longitudinally 2 elongate, very narrow; tabulae complete, 
horizontal, one-quarter millimetre apart. 
Ohs . — This species is remarkable for the length and regularity of 
growth of its corallites, the constant and peculiar form of its gonopores, and 
the narrow and slit-like nature of the mesopores, when present. In its erect 
and compact manner of growth it resembles II. cratus , more than any other 
Australian species ; but the relative sizes of the autopores will at once 
distinguish the two forms, to say nothing of the peculiarities of the other 
two sets of zooids just indicated. 
When a corallum is viewed macroscopically from above, without 
relation to the mode of growth or length of corallites, II. orlhopteroid.es 
might at first sight be mistaken for II. Sussmilchi, but the fenestrules are 
more labyrinthine than those of the latter ; and what is of more importance, 
1 ipSdirrepos — “ with high or upright columns,” and oides — “ resemblance.” 
2 That is to say, at right angles to the direction of growth of a corallite chain. 
3 That is to say, parallel to the 'general growth of the corallum, 
I) 
