IN THE LOWER TEETIAKT STRATA OF NEW ZEALAND. 195 



summit. Of this form, only tlie upper portion of a spicule is 

 known. The shaft ia "045 mm. in thickness. 



Spinulate or pin-shaped spicules, though very abundant, are 

 relatively less numerous in the Oamaru material than the acuate 

 and acerate forms. They vary considerably in size ; small forms 

 not exceeding '1 mm. in length by '01 mm. in thickness, whilst 

 the larger reach to 1*21 mm. by '045 mm. They correspond 

 very fairly with the spinulate spicules in recent sponges of the 

 Clavulina group belonging to the following genera : Suherites, 

 Polymastia, Cliona, and Spirastrella. Similar spicules are also 

 present in Esperella and Axinella. That some of the fossil spin- 

 ulates most probably belonged to Spirastrella is shown by the 

 occurrence of the characteristic spiral flesh-spicules of this genus 

 in the deposit. As detached, in dredgings by H.M.S. ' Egeria * 

 off the S.W. of Australia, they are present at depths of 2479 

 fathoms. 



Grapnel Spicule o/'Acarnus, Gray. 



PL IX. fig. 13. Spicule with evenly rounded head and straight 

 subcylindrical shaft, which terminates abruptly in a slight infla- 

 tion, from which five or six rays with recurved ends extend in a 

 generally horizontal direction. The axial canal has a slight 

 bulbous expansion in the head, thence it extends as a delicate 

 thread to the opposite end, where it is slightly enlarged, and 

 apparently sends out branches into the rays. The length of the 

 spicule is "21 ram. by '015 mm. in thickness. Spicules nearly 

 corresponding in form and size occur in the recent Acarnus 

 Wolfgangi, Keller (Zeit. f. wiss. Zool., Bd. 48, 1889, p. 399, 

 t. XXV. f. 56), from the E,ed Sea. The larger skeletal spicules of 

 this genus are acuates and tibiellas, similar to those which have 

 been already referred to. A detached grapnel spicule of Acarnus 

 with three simple rays is present in a dredging off theS.W. coast 

 of Australia at a depth of 2479 fathoms. 



Forceps or Hair-pin Flesli- Spicules q/Torcepia, Garter. 



Forcepia Carteri, n. sp.; — PI. IX. figs. 20, 21. Spicule curved, 

 resembling a hair-pin, the arms subcylindrical, thickest at the 

 curve ; at their ends they are slightly divergent, and one is a 

 little longer than the other; each arm terminates with a convex 

 slightly expanded cap or bulb. The surface covered with very 

 minute spines ; those on the arms are recurved in the direction 



14* 



