2 R. KIEKPATRICK. 



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

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

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



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

 length and • OG to • 08 mm. in thickness, straight, fusiform, tapering gradually to 

 very sharp ends. 



2. Choanosomal oxeas lying scattered between the radial filires, 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, G) with pointed conical cladome, with slender sharp- 

 pointed cladi each 225 ju, long, chorda 187 /x long; rhabdome about 12 mm. long, and 

 averaging al)0ut 20 ju. 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 /x long, chorda 118 /jl 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 /x long, with one cladus 28 //, in length, longer than 

 the other two ; cladal end of rhabdome slightly swollen. 



Microscleres. Sigmata 12 "3 /li-13/x long, 7"04 /x broad (when seen in C-like 

 aspect), and 1-5 jj. 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 nnn. 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. 



