68 PERCY SLADEN TRUST EXPEDITION 



stomodseum, not abundant at the bases of polyps. The terminal battery of each entocoelic 

 tentacle swollen but without much thickening of ectoderm, and nematocysts I and II h 

 mostly restricted to its tip ; the exocoelic terminal battery well formed with thickened 

 ectoderm and nematocysts closely packed ; 3 — 5 very small sub-terminal batteries ; 

 mucous vacuoles* found close together in all batteries, between which lie rod and spindle- 

 shaped nuclei homogeneously stained dark ; granular vacuoles also present. Stomodeeum 

 much compressed laterally ; its ridges narrow with no nematocysts. 



Entocoelic pleats present in outer half of primary mesenteries in the stomodseal I'egion 

 of polyps, best developed in outer one-third, broad and constricted at their bases, hence 

 appearing knobbed in transverse section, occasionally sub-divided, below stomodaeum 

 extending over two-thirds width of mesentery. Mesenterial mesoglsea slightly thickened 

 near stomodseal attachment, elsewhere thin. 



Ectoderm of oral-disc with columnar facies resembling that of C. chalcidicum. Endo- 

 derm of body- wall thin above enterostome, with few algse and many transparent vacuoles, 

 below becoming reticulated and consequently distended ; tentacular endoderm hardly 

 visible owing to aggregation of algse, sometimes blocking lumen of exocoelic tentacle in the 

 region of its terminal battery ; endoderm of primary mesenteries somewhat thickened near 

 their stomodseal attachments, behind filaments appearing pad-like in transverse section, 

 elsewhere thin ; algee massed together in exocoelic side. Stomodseal endoderm extremely 

 thin. 



Polyps examined, ten, 4 from one and 3 from a second specimen from Red Sea, 

 1 from a specimen from Salomon t and 2 from a specimen from Ceylon. 



Remarks. Gorallum. Milne Edwards and Haime's type of L. roissyana (locality 

 unknown) is a large specimen measuring 25x20x17 cm. It is peculiar in that the 

 corallum has incrusted over projecting calcareous tubes of some polychsete worms ; conse- 

 quently the corallites have undergone some modification in shape — most of them project 

 slightly, some almost circular, a few drawn out ; on the general substratum, the corallites 

 have the usual polygonal shape. As in my examples the septa are never in more than 

 four orders, but in many corallites more than twelve septa — up to thirteen — meet the 

 columella. 



In the Berlin Museum are two specimens, referred by Klunzinger to L. transversa, 

 one large and flat, measuring 24x 12 cm., the other small, both entirely resembling my 

 type specimens of the present species. Identical with these is another small specimen 

 referred by the same author to L. immersa. 



Localities. Red Sea (l 6 specimens). Chagos, Salomon (7). Maldives: Hulule (3) ; 

 Goidu (l) ; Addu (l). Minikoi (3). Ceylon (small specimens). Not known from the 

 Pacific. 



2. Leptastrea ehbenbergana, Milne Edwards and Haime. (PL 17, figs. 5 — 7 ; 18, 

 figs. 2 and 7 ; 19, figs. 3 and 4 ; 34, fig. 8.) 

 1850. Leptastrea ehrenhergana, Milne Edwards and Haime, Ann. Sci. Nat., 3" ser., xii, p. 120. 



* Mucous vacuoles stain orange with hsematoxylin and eosin as in Galaxea. 



t The polyps of this specimen were in a bad state of preservation ; in the one sectioned a few disconnected 

 ova were found. 



