REPORT ON THE HEXACTINELLIDA. 261 



out that the dense sieve-plate openings which occur abundantly on the truncated lateral 

 borders of the five-sided prismatic body, and are surrounded by delicate spicules project- 

 ing in a cuff-like manner, are the oscular openings of the main anastomosing canal system 

 running longitudinally in the walls of the sponge. The larger hollow spaces occurring 

 in the axis and opening above he designated pseiidogasters, and their terminal lattice- 

 work closing plates as pseudo-sieve-plates. A second system of passages and canals, which 

 lie between these exhalent oscular openings, separated from them by sponge tissue, and 

 covered towards the outside by fine dermal lattice-like networks were referred by 

 ]\Iarshall to the subdermal spaces of Haeckel, or to the intermargincd cavities of 

 Bowerbank. In consequence of these results of his examination, Marshall,^ in 1876, 

 characterised the genus Semperella in the following manner : — " Polyzoic with 

 pseudogasters. Anchor bundles anastomosing with each other throughout the whole body 

 wall. Dermal skeleton of cross spicules separated by the tissue of the body and spread 

 over large subdermal longitudinal spaces into which the internal canals open. Oscula of 

 the individuals in rows, with peristome wreath and sieve-plate. The gastral skeleton 

 formed of large four-rayed spicules, provided with meshes occlusible by means of fir-tree- 

 like spicules, and in direct connection with the dermal skeleton. The cavities of the 

 pseudogastral system are covered internally by six- and five-rayed spicules." 



Semperella schultzei, Semper. 



Near the Philippine Island, Zebu, the Challenger Expedition obtained a beautiful 

 specimen of Semperella schultzei, 38 cm. in length, and 5 to 7 in thickness. This form 

 having been well preserved in spirit, remains almost uninjured. The cylindrical body, 

 which measures 30 cm. in length exclusive of the basal tuft, has inferiorly a cylindrical 

 form, but becomes gradually wider upwards, forming an irregular pentagonal prism with 

 truncated edges. The latter are from 5 to 8 mm. in breadth, and from the middle of 

 the body upw\T,rds do not extend in exact longitudinal dii-ection, but extend on the one 

 hand obliquely, and further divide and anastomose, till they finally unite in the 

 superior flat cone, which occupies the terminal region of the upper end. The root- 

 process, which extends perpendicularly downwards from the lower end of the sponge, 

 becomes widened out inferiorly into a loose brush, and penetrates by means of its 

 diverging spicules into the very varied detritus-substratum. There was no trace of 

 commensal Anthozoa. 



It is noticeable, even with the unaided eye, that a striking difierence can be observed 

 in the structure of the external layer of skin on the above mentioned truncated lateral 

 edges, and that on the intervening flat, or even shghtly concave, lateral surfaces (10 to 30 

 mm. in breadth). For while the latter exhibit a very delicate narrow-meshed quadratic 



I Zeitschr. f. roiss. Zool., Bd. xxvii. p. 131. 



