198 DR. HINDE AND MR. HOLMES OK SPONGE-REMAINS 



rounded. Axial canal continuous through the spicule and opening 

 at both ends. Height '46 mm., thickness '018 mm. 



Bihamate spicules of the same character as those referred to 

 above are more especially present in the following genera of 

 recent sponges : EspereJla, Amphilectus, Myxilla, Forcepia, and 

 GladorTiiza. Bihamate spicules are known as fossil from the 

 Lower Lias upwards; but, as rule, those which have hitherto 

 been recognized from the Cretaceous and lower rocks are con- 

 siderably larger than those from Oamaru and in recent sponges. 



Glasp-Jioolc or Trenchant Bihamate Flesh-Spicules oj 

 Hamacantha, Gray. 



Samacantha Johnsoni ?, Bowk., sp. — PI. IX. fig. 33. Spicule 

 robust, smooth ; shaft nearly straight or with a slight curve, the 

 inner edge with a faintly-marked shallow curve. Ends contort,, 

 barbed, with distinct circular notch at the bend. Axial canal 

 continuous throughout the spicule, and opening at the ends of 

 both the hooks. Height "15 mm., greatest thickness of shaft, 

 including edge, "02 mm. A similar but smaller spicule is repre- 

 sented in fig. 37. 



Another form (PI. IX. fig. 34) is nearly similar to the pre- 

 ceding (fig. 33), but with a well-marked open notch or curve in 

 the central portion of the inner edge of the shaft. Axial canal 

 shown, but it is much finer than in the preceding. The barbed 

 ends may be either symmetrical or contort in various degrees, 

 just as in recent spicules of the same kind. These spicules 

 (figs. 33, 34) are strikingly similar in form and size to those of 

 the recent Hamacantha {Symedesmia) Johnsoni, Bowk., sp, 

 (Mon. Brit. Spong. voL i. p. 247, pi. v. fig. 112), from Madeira, 

 and in the same species from near the Faroe Islands, as figured 

 by Mr. Carter (Ann. & Mag. N. H. s. 5, vol ix. 1882, p. 296, 

 pi. xi. fig. 21 c, d). They correspond equally closely with those 

 in Vomerula esperoides, Eidley and Dendy (Chall. Eep. vol. xx. 

 p. 60, pi. xvii. fig. 2a, h), from the Agulhas Bank and off the 

 Eio de la Plata ; and these again, according to the same authors, 

 are similar to the spicules in Hamacantha papillata, Vosm. (Spong. 

 "Willem Barent's Exp. p. 28). It may be doubted if there are 

 sufficient grounds for separating Vomerula, Osc. Sch., from Ha- 

 macantha, Grray. In addition to the distinctive fiesh-spicules, 

 there are in the Oamaru material the corresponding acerate and 



