234 DB. HINDE A^D ME. HOLMES OF SPONGE-UEMAIKS 



same formatiou ia Kent and in the Upper Chalk of Norfolk. 

 Very similar spicules both, in form and proportion occur in the 

 recent Stelletta {Anthastra) pyriformis, Sollas, sp. (Chall. Eep. 

 vol. XXV. p. 146, pi. XV. figs. 3-7), from Port Jackson, at depths 

 of from 30-35 fathoms. 



Geodites (b). — PI. XIII. fig. 6. Trifid spicule, with straight, 

 scarcely tapering shafc and small furcate head-rays. The shaft 

 is incomplete, the portion remaining is 3'25 mm. in length and 

 •1 mm. in thickness ; the head-rays are '17 mm. long, 



PI. XIII. figs. 7, 8. Trifid spicules with straight, stout? 

 tapering shafts ; head-rays simple or furcate, their ends nearly 

 horizontal or slightly recurved. Axial canals distinctly shown in 

 the shaft and head-rays. Length of spicule "9 mm., thickness of 

 shaft '075 mm. to "1 mm. ; length of head-rays "2 mm. 



Stelletta (a). — PI. XIII. figs. 9, 10. Trifid spicules with stout 

 tapering shafts and short simple head-rays, projecting obliquely 

 forwards or slightly recurved at the ends. Length of spicule 

 1*75 to 2"6 mm., thickness of shaft '09 mm. ; length of head-rays 

 •225 mm. Similar forms occur in the Upper Chalk of Norfolk 

 (Hinde, Foss. Sponge Spic. pi. iii. figs. 7, 10) and in the recent 

 Stelletta reticulata, Carter (Ann. & Mag. Nat. Hist. s. 5, vol. xi. 

 1883, p. 352, pi. xiv. fig. 4 h), from the S. coast of Australia. 



PI. XIII. figs. 11-15. Trifid spicules with straight or curved 

 tapering shafts and short head-rays, either simple or furcate. 

 Fig. 11, which is much smaller than the others, is only '46 mm. 

 in length by '04 mm. in thickness ; the head-rays are nearly 

 horizontal and "084 mm. in length. In figs. 12, 13 the spicules 

 are 1'3 mm. in length and about '18 mm. in thickness ; the head- 

 rays, which are furcate and project obliquely forwards, measure 

 •3 mm. in length. In figs. 14, 15 the spicules are from '95 to 

 1-5 mm. in length ; the shafts are "09 mm. in thickness, and 

 the small simple pointed head-rays are only '1 mm. long. These 

 trifid spicules probably represent two or three species of Geodites 

 or Stelletta. 



PL XIII. figs. 1(5, 17. Trifid spicules Math elongate shafts and 

 relatively long, simple head-rays extending nearly directly for- 

 wards. The shafts are from "04 to '09 mm. in thickness : in 

 fig. 16 the head-rays are "24 mm. in length by "02 mm. in thick- 

 ness ; in fig. 17 the head-r?«ys are unequal in size, the longest 

 measures "67 mm. by "1 mm. in thickness. Similar 'fork' 

 spicules are known from the Chalk of Norfolk (Hinde, Foss. 



