232 DK. LIKDE AND MR. HOLMES OX SPOJs'GE-BEMAINS 



Western Australia (Mon. Brit. Spong. vol. i. p. 268, pi. x. 

 figs. 235, 236). 



Trijid Skeletal Spicules of TTi^toleraus, Sollas. 



Triptolemus australis, n. sp. — PI. XIII. fig. 34. Spicules with 

 a short fusiform shaft, pointed at both ends, from the centre of 

 which three divergent rays extend horizontally and dichotomize 

 three and occasionally four times. The rays are cylindrical or 

 compressed, smooth, those of the second or third subdivision not 

 always in one plane. All the rays are traversed by axial canals, 

 which open at tlieir extremities. Diameter of spicule '3 mm., 

 thickness of primary rays '03 mm. Sponges with spicules 

 similar to these were first described by Mr. Carter as PacJiastrella 

 intexia and P. parasitica (Ann. & Mag. Nat. Hist. s. 4, vol. xviii. 

 1876, pp. 409-10, pi. XV. fig. 41, pi. xvi. fig. 50). Subsequently 

 Mr. Carter placed these forms under the genus Samus (Ann. & 

 Mag. Nat. Hist. s. 5, vol. vi. 1880, p. 60), and they have since 

 been placed in a distinct genus by Prof. Sollas (Chall. Report, vol. 

 XXV. p. 93). It is very doubtful if the type species, T. cladosus, 

 Sollas, is distinct from T. parasiticus, Carter, sp. The Oamaru 

 specimens are notably larger than the spicules of recent forms, 

 and they probably indicate a new species, which may be provision- 

 ally termed Triptolemus australis. 



Trifid Spicules q/'Ditrisenella *, n. g. 



Ditrieenella Oamarue?isis, n. sp. — PI. XII. figs. 34, 3-5. Spicules 

 with fusiform shaft, pointed at both ends, and with two whorls of 

 trifid rays. Each whorl is at an equal distance from the end of 

 the shaft, and there is a short interspace in the centre of the 

 shaft between the whorls. The normal three rays of each whorl 

 are bifurcate; the rays are nearly horizontally extended, smooth, 

 conical and obtusely pointed. Axial canals traverse the shaft 

 and all the rays, and open at their ends. Length of shaft '19 mm., 

 thickness "025 mm. Length of rays '04 to '075 mm., thickness 

 •012 mm. Detached spicules of a similar character to these 

 forms are figured by Bowerbank under the names of ' Furcated 

 spiculated biternate,' and described as interstitial tension spicula 

 of Farrea occa (Mon. Brit. Spong. vol. i. p. 281, pi. ix. fig. 200 ; 



* Tpiaiva, a trident, dimia. 



