— 33 — 

 Stelletta? sp. 



(riate II fig. 9, 10.) 



Robust spicule with straightgradually tapering shaft and .simple 

 trifid head; the ra)s stout, short and recurved. In one example 

 the shaft has a contracted neck ; in others, the shaft is thickest 

 immediately beneath the rays. The incomplete spicule (fig. 9) 

 has a length of 4,04 mm ; width of head rays 0,63 mm ; thickness 

 of shaft 0,382 mm. The smaller but complete spicule (fig. 10) 

 is 2,76mm long; width of shaft 0,157mm. The interior 

 canals are partly preserved. These spicules are extremely rare. 



Spicules similar in shape but much smaller are figured 

 by O. Schmidt in Stelletta Grubii (Adriat. Spong. Taf. IV 

 fig. 2 a, b) and Dr. Bowerbank represents the 'zone' spicule 

 of Stelletta (Ecionemia) coactwa (Mon. Brit. Spong. Vol. Ill 

 p. 269 t"!. 82 fig. 16) with similar short curved head rays. 

 This .spicule occurs also in the Irish Chalk (Wright. : op. cit. 

 PI. II figs. 8. 9) and is referred by Bowerbank to Tethea and 

 Geodia. 



Stelletta? sp. 



(Plate II figs. II, 11 a.) 



Robust spicule with elongated gradually tapering shaft 

 and head of simple conical, pointed, relatively very short rays, 

 directed obliquely forwards. Length of specimen figured 

 3,98mm., thickness of shaft 0,24mm. ; width across the rays 

 0,54 mm. Rare. 



A spicule of similar form but only half the size is met 

 with in Stelletta Boylicii, O. Schmidt (Sp. d. Adriat. Meeres 

 p. 47 Taf. IV. fig. 4). The majority of the 'zone' spicules 

 of Geodia, Stelletta, etc., have the head rays much more 

 extended than is the case with this form of spicule. This 

 form has also been met with in the North of Ireland (Wright : 

 op. cit. Plate 11 fig. 9.) 



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