REPORT ON THE HEXACTINELLIDA. 'M7 



Ifiigtii, straight and capitate, pappiform, or occasionally of the first kind once branched, 

 or occasionally with echiuated heads." The difference between Dactylocahjx pumiceus, 

 8tutchbury, and Dactylocalyx pumicea, Gray = IphiteoJi ingalli, Bowerbank, Carter found 

 to consist in the fact that " the latter is charged, especially towards the surface, Avith long 

 linear spicules (slender, fusiform, slightly inflated, and spined for some distance at each 

 ond), while these are not to be seen in Dactylocalyx pumiceus, Stutchbury. 



In 1876 Marshall' placed the genus Dactylocalyx among his Pleionacidse, and 

 chax'acterised it in the following words : — " Fused latticed tissue of little regularity. 

 Free spicules are represented by rosettes and irregular hexradiate forms of unknown 

 significance." As species, he noted (l) Dactylocalyx pumiceus, Stutchbury, and (2) 

 Dactylocalyx crispus, 0. Schmidt. 



In 1877, in his paper on Stauronema,^ Sollas referred Dactylocalyx and Aphrocallistes 

 to his family of the Aphrocallistidse, distinguished by " sex-radiate skeleton spicules with 

 rays making any angle with each other," and in an article On the Action of Caustic 

 Potash on the Siliceous System of Sponges,^ he pointed out the irregular arrangement 

 of the spicules in the skeletal framework of Dactylocalyx pumiceus and Dactylocalyx 

 sxilxjlohosus. 



In 1877, in his studies on fossil sponges,* Zittel referred Dactylocalyx with Pei-i- 

 p)hragella, Marshall, and Mylitisia, Gray, to his Mseandrospongidae, which consist of 

 meandering, entangled, and simple anastomising tubes or plates. 



In the Journal of the Microscopical Society,'* Sollas described a simple plain cup- 

 shaped variety of Dactylocalyx pumiceus, Stutchbury, which he named Dactylocalyx 

 pumiceus, var. stutchhuryi, or simply Dactylocalyx stutcliburyi. He called attention 

 to the typical alternation of the outer and inner, or upper and under radial furrows or 

 furrow-like depressions, described the continuous skeletal framework composed of united 

 hexradiate spicules, and further some six-rayed, five-rayed, and simple s^^indle-shaped 

 or thread-like isolated " flesh spicules." At the knots of these originally isolated six- 

 rayed spicules, which are here united to the skeletal framework without recognisable 

 order, Sollas frequently saw the beginning of a hollow octahedron, such as occurs in the 

 Ventriculites. This was seen to become so completely covered by siliceous lamellae that 

 the knots in the older portions of the framework appeared to be solid throughout. 



Among the Hexactinellida procured by the American Expeditions from the West 

 Indies, and examined by Oscar Schmidt in 1880, several species of Dactylocalyx 

 were found, which corroborated on the whole the opinions of Sollas. The form which 

 had previously been described by Schmidt as Dactylocalyx crispus was now separated 

 from the genus, and regarded as a young form of Schmidt's Syringidium zittelii. 



• Zcilschr.f. wiss. ZooL, Bd. xxvii. \). 122. ^ Ann and May. Nat. Hist., ser. 4, vol. .\i.\. \k 1. 



^Ann. and Mag. Nat. Hist, ser. 4, vol. x.v. pp. 285-300. * Abhandl. d. k. Baier. Akad., vol. -xiii. p. 38. 



!■• Vol. ii. pp 122-133. 



