K. KIRKPATRICK. 



groups in grooves between the ridges. Flagellated chambers eurypylous. Cortical 

 skeleton formed of palisade-like rows of oxeas and fan-like bundles of trichodal 

 protriaenes, occurring only in the root-tuft zone and poral zone. 



Spicules. Megascleres. 1. Somal Oxeas (VIII. 10)* from 5 to 13 mm. in 

 length and 06 to ' 08 mm. in 'thickness, straight, fusiform, tapering gradually to 

 very sharp ends. 



2. Choanosomal oxeas lying scattered between the radial fibres, 1-3 mm. long and 

 ' 04 to ' 06 mm. thick. 



3. Cortical oxeas (VIII. 13) almost straight or slightly curved, 1 12 x 0'04 mm. 



4. Anatriaenes of two kinds, each varying in length and tapering to a filiform 

 extremity. 4a. (VIII. 5, 5a, 6) with pointed conical cladome, with slender sharp- 

 pointed cladi each 225 p. long, chorda 187 p. long; rhabdome about 12 mm. long, and 

 averaging about 20 p, broad, thick below cladal origin, then with a slender neck followed 

 by long thicker portion tapering finally to filiform extremity. 



Anatriaenes, 4b (VIII. 7, 7a) common in root-tuft, with thick rounded conical 

 cladome, with short thick cladi 118 p. long, chorda 118 p, long; rhabdome of nearly 

 uniform diameter till it tapers off to filiform extremity, length varying from 10 to 

 40 mm. 



5. Protriaenes. Cladome commonly with one cladus 0*135 mm., longer than the 

 other two, though there may be two equal long ones, or they may all be equal ; 

 rhabdome fusiform, tapering to a filiform extremity, on an average about 9 x 0'054 

 mm. in length and thickness. 



6. Trichodal protriaenes 218 p. long, with one cladus 28 p. in length, longer than 

 the other two ; cladal end of rhabdome slightly swollen. 



Microscleres. Sigmata 12 '3 p.-l3 p, long, 7 '04 /x broad (when seen in C-like 

 aspect), and 1 5 p thick, surface micro-punctate. 



There are five specimens of this sponge, four large and one very small. The 

 largest (VIII. 1) is a fine example with a root-tuft; this appendage not being present 

 in the other large specimens owing to having been torn away when the sponges were 

 uprooted from the sea-bottom. 



The body of the largest specimen is 10'5 cm. long and 11 '5 cm. in broadest 

 diameter, and of the smallest 10x8 mm. in length and breadth. The mass of root- 

 tuft in the type specimen is about 4 cm. in thickness. 



The surface pile of spicules varies considerably in its degree of development ; in 

 two examples the surface is almost bare ; in two others the pile is soft, and about 3 to 

 4 mm. in height, with oscular fringes about 4 5 mm. in height. The pile is formed 

 mainly of the projecting triaenes of the radiating fibres of the skeleton, each fibre 

 spreading out fan- like in an oblique or vertical plane. In the specimens bare of the 

 pile, the boundary between the poral and oscular zones (VIII. 2) is a fairly well marked 

 circular line of demarcation situated at the junction of the upper fourth and lower 



* Roman numerals followed by Arabic refer respectively to the Plate and figures ; thus (VIII. 10) means 

 Plate VIII., fig. 10. 



