IN THE LOWEE TERTIAET STRATA OE FEW ZEALAND. 203 



witli stout curved shaft having three palms or teeth at the upper 

 end ; the lateral ones widely extended and curved, horn-like, the 

 central tooth projecting prominently forwards and downwards. 

 The opposite end o£ the spicule is sub triangular, the lateral 

 palms with revert margins inwardly curved above, and a pro- 

 minent elongate tubercle with rounded ends. Length of spicule 

 •037 mm., width across upper palms '025 mm., length of lower 

 palms "025 mm,, thickness of shaft 'Ol mm. Fig. 49 is a front 

 view, and figs. 50, 51 lateral views of the same form of spicule. 

 Fig. 62 is a much smaller form which may be only a young stage 

 of the larger spicules. In a front view of this, the central 

 tubercle (?) of the upper end projects as a circular or slightly 

 elliptical process, and beneath it is an elongate spatulate tooth or 

 palm ; the tubercle of the lower end of the spicule is subtrian- 

 gular in outline. The length of this spicule is '02 mm., width 

 across the teeth '014 mm. 



The only recent spicules with which these forms can be com- 

 pared are some peculiar anchorates described by Osc. Schmidt in 

 Sceptrella regalis, from off Florida (Atlant. Spong. p. 58, pi. v. 

 fig. 24 c). In these the larger end of the spicule is propor- 

 tionately less widely extended than in our fossils, but the 

 anterior palm has a similarly projecting tongue-shaped process. 

 According to Osc. Schmidt, these anchorates are associated with 

 '' sceptrella " spicules; but Mr. H. J. Carter, and subsequently 

 Ridley and Dendy, consider that this association of such dif- 

 ferent forms in one sponge arises from a mistake, and that the 

 anchorates really belong to a species of Myxilla (Ann. & Mag. 

 N. H. s. 5, vol. iii. 1879, p. 359 ; Chall. Rep. vol. xx. p. Ixii, 

 note). In accordance with tins view, the present fossil spicules 

 may be referred to Myxilla, and as they indicate a new species, 

 it may be termed Myxilla Dendyi. 



Desmacidon (a). — PI. IX. fig. 40. Short stout equianchorate, 

 the central portion of the shaft inflated, with neck-like constric- 

 tions above and below ; teeth curved, stout, bent inwards, 

 anterior prominent. Length of sjDicule '028 mm., of teeth '01 

 mm., greatest width of shaft '01 mm. The anchorates in Desma^ 

 cidon tunicata, Os. Sch. (Atlant. Spong. p. 55, pi. v. fig. 21 h), 

 are approximately similar to this form, but their shafts are not 

 inflated. 



Desmacidon (b). — PI. X. fi?. 36. Equianchorate with curved 

 shaft, slightly constricted in the middle and at both ends ; lateral 



