CYTHERE HARRISIANA. 17 



p. 17) had longitudinal lines of much smaller punctations, as shown by a broken 

 specimen from the Sponge-gravel of Faringdon, Berks. 



One of the recent forms nearest to G. Harrisiana is C. favoides, Brady, 

 Annals, ' Mag. Nat. Hist.,' ser. 4, vol. ii, 1868, p. 222, pi. xv, figs. 5—7, from 

 Tenedos. The male (fig. 5) is narrow; the female (fig. 6) is broader (higher). 

 The carapace is not so angular, and it has a different style of ornament. The 

 Cretaceous G. interrupta, Bosquet, with which it was at first confused, has some 

 features even more similar, but its central ridge is too strong. 



Young individuals are not uncommon in Mr. F. Chapman's collection from the 

 Gault of Folkestone. They have a subquadrate outline like fig. 45, but each of 

 the posterior angles of the body of the valve is produced as a spine. 



Fig. 47 = 6 a. Detritus, Charing. (Type.) 

 Fig. 48 = 6 b. Gault, Leacon Hill, var. a. 

 Fig. 49 = 6 c. Gault, Folkestone, var. (3. 



6 d. Gault, Folkestone, var. /3. 

 Fig. 50 ::= 6 e. Detritus, Charing, var. a. 

 Fig. 51 = 6/. Gault, Leacon Hill, var. a. 

 Fig. 52 = 6 ^. Gault, Folkestone, var. /3. 



6 h. Detritus, Charing, var. /3. 

 Fig. 43. Gault, Folkestone, var. 8, setosa. 

 Fig. 44. Gault, Godstone, var. 3, setosa. 

 Fig. 45. Gault, Folkestone, var. S, setosa. 



Lower Greensand, Faringdon, var. y. 

 Fig. 46. Gault, Folkestone, var. e, reticosa. 



Localities. — This species has been found in the Ghalk, Woolwich, at several 

 places in co. Antrim, and at Keady Hill, co. Londonderry ; Detritus, Charing ; 

 Gault, Folkestone, Leacon Hill, and Godstone ; Greensand, Cambridge and Black- 

 down ; Loiver Greensand, Faringdon. A similar form occurs in the Portland Oolite 

 at Ridgway, Dorset. 



3*. Cythere Hakeisiana, Jones, var. setosa^ nov. Plate I, figs. 43 — 45. 



Fig. 43. Length -84 



Fig. 44. „ -72 



Fig. 45. „ -56 



heiffht '44 mm. 



53 '4 ,, 



■36 „ 

 This form is much like that shown by fig. 48 (old Monogr., fig. 6 i), but it is 

 more convex and inclined to have a ridge along the middle, and its posterior 



3 



