282 Mr. A. Dendy on a new Species o/" Cladorhiza. 



the surface of the mud upon the long, slender stalk, the animal 

 being anchored in the mud by means of the delicate rootlets. 

 This view of the position of the body in life is confirmed by 

 the fact that there is an egg-capsule of some mollusk 

 attached to the stem just at the point where it branches into 

 rootletSj and in order that this attachment might take place, 

 the stem must have been entirely out of the mud. In 

 presence of the facts now ascertained * with regard to 

 the existence of contractile (muscular) tissue in the Porifera, 

 there is no great improbability involved in the supposition 

 that the arms or pinnae of GladorMza pentacrinus may be 

 endowed with some slight power of motion, although it is 

 very difficult to see how any advantage to the sponge could 

 arise from the possession of such a power. Unfortunately the 

 condition of the specimen quite precludes any investigation 

 as to the presence of contractile iibre-cells {myocytes, Sollas) 

 in the arms. In a species of the allied genus Espe7^ella {E. 

 Murrayi), however, it has been shown by Ridley and Dendy f 

 that there is a well-developed system of undoubtedly contrac- 

 tile fibrous tissue, whose function is to open and close the 

 peculiar crack-like pore-areas, and thus to regulate the supply 

 of water. 



In the peculiarity of the chelas the species stands quite apart 

 from all others of the genus, in which, it will be remembered, 

 the small end of the chela is usually very poorly developed. 



The species is of further interest owing to the fact that no 

 other Monaxonid sponges were obtained at the same station, 

 which is hence totally unrepresented in the Report on the 

 Monaxonida. 



EXPLANATION OF PLATE XV. 



Cladorhiza pentacrinus, n. sp. 



Fig. 1. The entire spong-e, X 6 : a, the egg-capsule of some mollusk 

 attached to the stem. 



Mg. 2. The upper portion of one of the pinnse, X 35, showing the ar- 

 rangement of the spicules. 



Ftg. 3. Two terminal rootlets, x 130, showing the arrangement of the 

 spicules. 



Fig. 4. A large stylus from the upper part of the stem, x 130. 



Fig. 5. The terminal stylus of a rootlet, x 250. 



Fig. 6. A tridentate anisochela, front view, X 700. 



Fig. 7. Ditto, side view, x700. 



Fig. 8. Ditto, end view, from the large end, x700. 



Fig. 9. A full-grown sigma, X 700. 



Fig. 10. A smaller sigma, X 700. 



* Cf. Sollas, article " Sponges " in ' Encyclopedia Britannica,' ed. ix. 

 p. 419 ; and Ridley and Dendy, Pteport on the ' Challenger ' Monaxo- 

 nida, Introduction, chap. ii. 



t Heport on the ' Challenger ' Monaxonida, pp. xxx, xxxix, 68, pis. 

 xiii., xiv., xlviii. 



