23 
V.— DESCRIPTION OF THE SPECIES. 
Genus — II ALY SITES, Fischer cle Waldheim , 1813. 
(Zoognosia, 3rd. Edit., 1813, p. 287.) 
A. — Spiniform Septa absent. 
HALYSITES LITIIOSTROTONOIDES , 1 Sp. tWV. 
(Plate T, Fig. 1 ; PI. IV, Figs. 1 and 2 ; PI. IX, Fig. 4.) 
Sp. Char. — Corallum consisting of a pyriform bunch of corallites 
subradiate from a common base, forming colonies at least five inches high 
and four inches wide. Eenestrules polygonal (pentagonal, hexagonal, and 
heptagonal), occasionally irregular or labyrinthine, but, on the whole, very 
regular, compact, and reminding one of a rouglily-laid tesselated pavement ; 
sizes 2x2 mm., 3x2 mm., 4x2 mm., 5x1 mm., 5x2 mm., and so on ; 
margins nearly straight, in one alignment ; Avails flat, i.e., in one plane, and 
to all intents and purposes level, barely at all ribbed or corrugate. Corallites, 
in general, long. Epitheca, transversely striate. Corallite chains farcimen- 
tiform only in the \ r ery slightest degree, hardly at all undulating the outlines 
of the fenestrules. Autopores long, parallelogrammatic, and very regular in 
form, margins straight ; from one to four in each corallite chain, five being 
the greatest number observed, and three the average; from three- quarters to 
one millimetre in length by one-third millimetre in width ; visceral chambers 
nearly square in longitudinal section ; tabulae complete, horizontal, half 
millimetre apart. Gonopores larger than the mesopores, polygonal (pentagonal, 
or hexagonal), and a feAV quadrangular ; walls as thick as those of the 
mesopores. Mesopores quadrangular to parallelogrammatic, and narrow ; 
longest diameter about one-quarter millimetre, at right angles to the direction 
of the corallite chains ; walls less in width than those of the autopores, and 
often showing a dark dividing line; tabulae complete, horizontal, one-quarter 
millimetre apart; visceral chambers longitudinally parallelogrammatic. 
C bs . — This coral, viewed macroscopically, presents a very regular and 
compact appearance ; so much so, that when the corallites are seen, either 
in weathered condition or in transverse section, the autopores and mesopores 
have a general resemblance to the septate filamentary thallus of an alga, and 
the united chains to a roughly-laid tesselated pavement. 
The farcimentiferous outline of the corallite chains is all but absent, 
and, in consequence, the margins of the calices are nearly straight in one 
continuous alignment, and the faint corrugation of the fenestrule walls, as a 
\i66(TTpwi ov, ref — “a tesselated pavement,” and oides — “ resemblance. 
