628 COLLECTIONS FROM THE WBSTEElf INDIAN OCEAN. 



CALCAEEA. 



No Calcarea from this district are recorded in Hackel's ' Kalk- 

 soh-wamme' (1872) j but Scliuffiier (Jenaisch. Zeitsch. xi.) in 1878 

 described several species from Mauritius, where they were collected 

 by Prof. Mobius. 



LEUCONID^. 



Two very widely distributed known species, a second species 

 added to a hitherto monotypic genus (Leueortis), and a known 

 Mascarene species, aU belonging to the Leuconidae, represent in this 

 collection the Calcarea of the Western part of the Incdan Ocean. 



53. Leucetta pirimigenia, var. megalirrliaphis. 



Leucetta primigenia, var. megaraphis, Hdckel, Kalkschwamme, ii. 

 p. 118. 



Two subglobular specimens 9 and 18 millim. in. diameter, re- 

 spectively, of the Dyssyeus-iann.. Colour in spirit pale brown. 

 Hackel states that this variety is rare, but does not give localities. 

 In the specimen which I esamined, the small triradiates are chiefly 

 confined to a thin cortical layer. 



Hah. Seychelle Islands, 12 fms. 



Distribution of species. Almost cosmopolitan. 



54. Leucaltis bathybia, Hachel, var. mascarenica, nov. 

 (Plate LIV. figs, a, a'.) 

 Kalkschwamme, ii. p. 156, pi. xxviii. fig. 2. 



Some specimens of the Amphoriscv,s-ioTm, composed of branching 

 and anastomosing tubes, cylindrical or somewhat compressed, 2-5 

 to 3'5 miUim. in diameter ; lumen 1-5 to 2*5 millim. wide, wall 

 about '5 millim. thick. Colour dull umber-brown to cream-colour. 

 The large quadriradiates are very large, viz. rays about "07 millim. 

 thick, and rather short, with a long apical ray projecting into the 

 cloacal cavity, and frequently a basal in the same plane but opposite 

 to the apical ; the small triradiates and quadriradiates are very small, 

 viz. rays about "007 millim. thick, and most commonly have the 

 forms figured in figs. 2c, 2d oi Hackel's plate (I. c), viz. with very 

 large facial angle. The larger triradiates are usually regular, and 

 their rays are about '04 millim. in diameter. The slight thickness 

 of the body-wall, the proportions of the spicules, and the general 

 form of the specimens (which is simply cylindrical in Hackel's 

 specimens) distinguish this form from yarr, perimina and arabica, 

 Hackel ; but in the straight or but slightiy curved spicular rays it 

 approaches most closely the latter variety. 



Hah. Darros Island, Amirante group; SeycheUe Islands, 4-12 fms. 



Distribution of species. Eed ^lea, (B.'dcheT) ; Port Jackson (Part I., 

 p. 482, of this Eeport). 



