EXPLANATION OF ITIK PLATES. 



683 



Plate LIV.* 



Fig. a. Leucaltii bathybia, var. mascarenica, the two forms of stout 

 quadriradiate and the fcriradiate spicules of the main 

 skeleton. x38. <i . The minute tri- and quadriradiates 

 of the cloacal surface, x 370. From type specimen from 

 Seychelle Islands. 



b. Aocinella spiculifera, two sizes of the skeleton- spicule, x 68. 



From specimen from Darros Island. 



c. A. proliferans, the skeleton-spicule, x 68. From type 



specimen from Providence Island. 



</. Leucortis anguinea, the stout acerate, and different forms 

 of the tri- and quadriradiate spicules of the main ske- 

 leton, x 68. d', the slender acerate (?) of the peristome 

 (the outer end imperfect), x 370. From type specimen 

 from Providence lleef. 



e. Erylus cylindrigerus. part of the disk-spicule, in profile, x 190. 

 e, the disk-spicule, from the front (tubercles omitted, 

 except at apex), x 190 ; ee", the same, the tubercles, x 300 ; 

 < •'", the cylindrical spicule, two forms, x 68 ; e"", the mi- 

 nute acerate spicule, young and adult, X 190 ; e""\ larger 

 stellate spicule, two forms, showing variation in the num- 

 ber and spination of the rays, x 190 ; e""", the small 

 stellate, x 370. From specimen from Providence Reef. 



/. Esperia gelatinosa, the subspinulate, /', large, and /*", 

 small anchorate (the latter from the front and side), 

 /", bihamate spicules ;/'", trichite-bundle. x370. From 

 specimen from Providence Island. 



g. Glathria decumbens, the skeleton and echinatiug acuate 

 spicules, x 190. g', the equianchorate flesh-spicule, from 

 the front and side, x 370. From type specimen from 

 Etoile Island. 



* Note. — The figures in this Plate have been prepared with the aid of 

 sketches, to scale, made by Mr. Ridley. 



