Mr. H. J. Carter on the Lithistidse. 437 



LIV. — On the HexACTINELLID^E and LiTHlSTlDiE generally, 

 and particularly on the Aphrocallistidse, Aulodictyon, and 

 Farrese, together with Facts elicited from their Deciduous 

 Structures, and Descriptions respectively of Three Neio 

 Species. By H. J. Carter, F.R.S. &c. 



[Concluded from p. 373.] 



Let us now turn our attention to the Lithistidas, of which the 

 following is a similar list of those also that have been brought 

 to notice. 



Lithistidse*. 



General character. Spicules developed upon a quadriradiate 

 division of the central canal, held together by amorphous 

 sarcode and an interlocking of their filigreed arms, forming 

 a reticulated glassy structure, whose interspaces are more or 

 less irregular and curvilinear. Composed of two kinds of 

 " skeleton-spicules," viz. those which form a layer on the 

 surface and are accompanied by minute or " flesh-spicules " 

 characterizing the species, and those forming the body, which 

 are more or less alike in all the species and accompanied by 

 fewer flesh-spicules. The skeleton-spicules of the surface, 

 which, for the most part, are provided with a smooth, pointed, 

 vertical shaft, directed inwards, and a horizontal head of dif- 

 ferent shapes according to the species, will be termed "surface-;" 

 and the spicules of the body, which interlock with their neigh- 

 bours through a filigreed development of all the arms, will be 

 termed " body-spicules." 



Species in which the surface-spicule consists of a shaft and three 

 straight bifurcated arms all smooth and pointed. 



Minute spicules of two kinds, viz. one acerate, fusiform, 

 slightly curved and microspined ; the other subspiral, sinuous, 

 tuberculo-spined. 



Dactylocalyx Bowerbankii, Johnson. Azores. (1) 



Masoni, Bowerbank. Madeira. (2) 



Corallistes typas, Schmidt. Florida. (3) 



* Abbreviations the same as in footnote, p. 357. 



1. B.M. P. Z. S. 1863, p. 259,= P. Z. S. 1869, p. 94, pi. vi. figs. 6, 7, & 8, 

 z=MacAndrewia azorica, Gray, P. Z. S. 1867, p. 507. 



2. P. Z. S. 1869, p. 91, pi. vi. figs. 1-4. 



3. Atlantisch. Spongienf. pi. iii. f. 3. 



4. B.M. P. Z. S. 1868, p. 565, fig. 1. 



5. P. Z. S. 1869, p. 89, pi. v. figs. 6-11. 



