REPORT ON THE HEXACTINELLIDA. 299 



Genus 2. Perii^hrageUa, MarsliaU (Pis. LXXX., LXXXL). 



1875. Marshall, Zeitschr. f. wiss. Zool., Bd. xxv. Suppl., p. 177. 



1876. Marshall, Zeitschr. f. wiss. Zool., Bd. xxvii. p. 113. 



History. — Among the Hexactinellida which Marshall described in 1875 in the 

 Zeitschrift flir wissenschaftliche Zoologie, there was a cup-shaped sponge about 15 cm. in 

 height from the Moluccas. On the lateral walls of this " there are curious tubuliform 

 individuals, which have coalesced and communicate with one another, and are provided 

 with a labyrinth of internal canals. They are sometimes broad and flat, sometimes 

 tubuliform, but always very slender." Marshall has applied to this form the name 

 Periphragella elisse. 



The network of siliceous beams, which is very dense beneath, but more diffuse above, 

 presents a tolerably regular structure with permeating square meshes, and very small 

 plain, round knobs on the surface of the beams. Of free spicules Marshall found (1) 

 smooth hexradiate spicules ; (2) simple five-rayed spicules, the unpaired principal ray 

 being twice as long as the others ; (3) small hexradiate spicules with concave terminal 

 discs, with five circularly disposed teeth on the margin of each ; (4) somewhat larger 

 hexradiate forms in which the rays are divided about the middle of their length into from 

 two to four pointed prongs; (5) broom-shaped spicules with a smooth shaft, on the 

 expanded extremity of which there are four somewhat diverging clubs, whose circular 

 terminal knobs are provided with zones of plain recurved tubercles. All these spicules 

 occurred exclusively in the middle and upper parts of the sponge ; in the base only small 

 smooth hexradiate spicules were found between the lattice-like network of beams. 



In his statement in regard t© the afiinities of the Hexactinellida,^ Marshall summa- 

 rised the characters of the genus Periphragella in the following words : — " Polyzoic, indi- 

 viduals conical, mouth naked, with conspicuously developed goblet-shaped pseudogasters. 

 Spicules sometimes hexradiate or simple dentate rosettes. Broom spicules with four 

 regular teeth. Special closing spicules for the dermal pores. Lattice-work very regular." 



Peri2)hrageUa elisai, Marshall (PI. LXXX., PI. LXXXL). 



Among the dried Hexactinellida which Dr. Doderlein acquired in Enoshima (Japan), 

 there were three specimens of Perijyhragella elisw, Marshall. One of these, which is 

 figured on PI. LXXX. fig. 1, has the form of a slightly bent cup or funnel 15 cm. in 

 length. This rises with a round hollow stalk of 12 mm. in diameter, from an irregularly 

 formed basal plate from 30 to 40 mm. broad, and gradually expands upwards towards 

 the round terminal opening, which is 50 mm, in breadth. The thin plate which directly 

 surrounds the lumen of the funnel is continued, above the stalk region, into numerous 

 radially disposed tubes of various width (from 3 to 15 mm. or more). These in most 



' Zeitschr. f. vnss. Zool, BJ. xxvii. p. 113. 



