OPHIEAPHIDITES. 23 



Genus TALPINA, Von Hagenow, 1840. 

 The simple tubular borings on which Von Hagenow has constituted this genus 

 differ so much from all those which we know to be produced by boring sponges, that 

 they can hardly be regarded as the work of sponges. The examples of T. solitaria 

 and T. ramosa. Von Hagenow, figured by Prof. Morris in the Ann. & Mag. Nat. Hist. 

 1851, vol. viii. t. 4. f. 4, 6 «, are in the Museum. 



Order TETRACTINELLID^, Marshall. 

 Genus OPHIEAPHIDITES, Carter, 1876. 



Ophiraphidites anastomans, Hinde, n. sp. (Plate I. figs. 4, 4 a.) 



Sponges growing in irregularly shaped masses, composed of loosely disposed tissues 

 which anastomose together. The tissues are from 2 to 4 mm. in width ; they are 

 composed of irregularly curved acerate spicules which are, as it were, loosely felted 

 together. Mingled with the curved spicules there are also a few straight forms ; 

 but I have been unable to detect any trifid spicules in the general mass. An average 

 large spicule is 2 mm. in length by -09 mm. in width ; spicules of much smaller 

 dimensions are mingled with the larger. 



There are two examples which 1 refer to this species. One, preserved in soft 

 chalk (Plate I. fig. 4), shows, in what is apparently a vertical section, the disposition 

 of the tissues and interspaces of the sponge : the spicules in this example are now 

 replaced by iron-rust ; but their forms can be pretty clearly ascertained. The other 

 example is preserved in the interior of a chalk flint, and exhibits a flattened, uneven 

 mass of spicules of the same forms as those of the chalk specimen. From this mass 

 the forms figured (fig. 4 a) have been selected. 



This species differs from the Ophiraphidites cretaceiis, Zittel*, in the open locular 

 character of the sponge. The spicules also are generally smaller; and no trifid 

 spicules have been detected. Detached spicules of a similar form to those of this 

 species are very common in the interior of flints from the Upper Chalk of this 

 country, and in strata of the same age in Westphalia and Hanover; they also occur 

 in the Eocene of Brussels; but it is extremely rare to find them still associated 

 together retaining their original positions in the sponge. 



It seems somewhat anomalous to include this species in the Tetractinellidse when 

 no four-rayed spicules have been detected in it ; and I can only justify placing it here 

 from the close resemblance of its curved acerates to those of 0. crefaceus, Zitt., in 

 which trifid spicules are also present, though rarely ; and it seems to me not impro- 

 bable that with more perfect examples they would be found in this form as well. 



Distribution. Upper Chalk : South of England. 



* Studien, III Ab. p. 8, t. xi. f. 2 a, b, c, d. 



