190 DE. HINDE AND MK. HOLMES ON SPONGE-EEMAINS 



Pi. VIII. fig. 10. Sliglitly curved acuate, very gradually 

 tapering from the head to the acutely-pointed apex. Length 

 •665 mm., thickness -017 mm. 



PI. VIII. fig. 10 a. E-obust, short, nearly straight acuate, 

 nearly cylindrical throughout, abruptly pointed near the apex. 

 Length '54 mm., thickness -04 mm. 



PI. VIII. figs. 11, 12. Evenly curved acuates, heads rounded, 

 thickest in central portion of the shaft, tapering in lower third, 

 somewhat abruptly pointed. Length '56 to '6 mm., thickness 

 •03 mm. Similar but slightly larger forms are present in Myxilla 

 liastata and M. spongiosa, Eidley & Dendy (Chall. Eep. vol. xx. 

 p. 134, pi. xxvii. figs. 1, 3), from off" the mouth of the Eio de la 

 Plata at a depth of 600 fathoms. 



PI. VIII. figs. 13, 14. Short curved acuates, thickest a short 

 distance below the head, tapering from the lower third. Length 

 of fig. 13, -352 mm., thickness "02 mm. Pig. 14, length -175 mm., 

 thickness '01 mm. In this latter the axial canal is widened for a 

 short distance below the head, vs^hilst in fig. 13 it appears as an 

 extremely fine even thread throughout its length. 



PI. VIII. fig. 15. Slender, elongate, slightly curved acuate, 

 shaft thickest a little below the middle of the spicule ; near the 

 apex it tapers somewhat abruptly. Length "485 mm., thickness 

 •009 mm. 



PL VIII. figs. 16-20. Short, stout, curved, comma-shaped 

 acuates, tapering from the middle, thickest at or near the head. 

 Length "095 to "58 mm., thickness *015 to '04 mm. Though 

 varying considerably in dimensions, these forms exhibit similar 

 characters. Spicules of corresponding form and size occur in 

 Axinella spiculifera, Lam., sp., and in A. proliferans, Eidley 

 ('Alert ' Heport, pp. 617-8, pi. liv. figs, h, c), the former from King 

 Island, Australia, the latter from Providence Island, Mascareue 

 Grroup, at depths of from IS to 22 fathoms. 



PL VIII. fig. 41. Curved acuate, nearly uniformly cylindrical 

 throughout, abruptly pointed near the apex. Length '37 mm., 

 thickness •Ol mm. 



PL VIII. figs. 22, 23. Straight acuates, fusiform, summits 

 evenly rounded, shafts increasing in thickness to near or below 

 the centre, thence gradually tapering to the apex. Length "36 to 

 '5 mm., thickness ^016 to "021 mm. These forms have the same 

 general appearance as the skeletal spicules of Tethya, Lam., but 

 they are much smaller. 



