32 C. F. JENKIN. 



to 160. Apical rays sharply pointed, slightly irregularly bent, 70 ft to 



WO p. long X 12 ft thick; set-off slight; angle between apical ray and 



basal ray 165. 

 Oscular Spicules. The fringe consists of hair spicules, and stout oxea of types 



(c) and (a) : 

 (/) Small quadriradiates from the oscular edge. Basal ray straight, tapering, 



and rather bluntly pointed, 100 ft to 120ft long ftx9fitolOft thick. 



Paired rays about equal, bent downwards, 50 ft to 100ft long x 7 ft to 



8 ft thick. Oral angle about 150. 

 (cf) The quadriradiates from the oscular collar are similar to (/), but much 



larger. Basal rays 220 p- or more long ; paired rays up to 200 /A long ; 



apical rays up to 120 p. long. 



ACHRAMORPHA GRAKDINIS. 



(Plate XXVII., Fig. 4, and Plates XXXIV. and XXXV., Figs. 103-104.) 



There is only one broken specimen of this new species in the collection ; it consists 

 of the upper part and oscular collar of a sponge which probably was of considerable 

 size, judging by the size of the oscule (see Fig. 4). The specimen is straight, 18 mm. 

 long, and circular in section, tapering from 4 to 3 mm. in diameter at the oscular 

 end. The lower part is covered by long oxea, which lie along the surface pointing 

 downwards ; the upper part is smooth and transparent. There is no fringe. 



The structure of the body wall is the same as in the other species of this genus. 

 There are no hair oxea, but there are a few small prickly hastate oxea in the dermis. 



The oscule (see Fig. 104) differs considerably from the other two species. There 

 is no fringe of hair oxea and no special ring of quadriradiates at the edge, the skeleton 

 being made up of both tri- and quadriradiates lying tangentially. The transition from 

 tangential quadriradiates to chiactines occurs in the same way as in the other species. 

 The basal rays of the chiactines project a long way outside the dermis. 



Spicules (Fig. 103). 

 Oxea. There are two sorts of Oxea : 



(a) Very large straight projecting oxea, size of longest fragments 3' 5 mm. x 



23 ft. Very sharply pointed at the inner end. 



(b) Small hastate oxea, from the dermis. Slightly irregularly bent, some 



spined, some smooth, 65 ft to 120 ft long, 3 ft to 6 p, thick. 



The Triradiates are of one sort : 



(c) Large, alate triradiates from the dermal cortex. Basal rays straight, 



tapering uniformly to a sharp point, 420 ft to 500 /* long x 12ft to 15 ft 

 thick. Paired rays usually equal, straight or bent slightly downwards, 



