143 INFEUIOR OOLITE AMMONITES. 



D'Orbigny's figures (loc. cit., excluding figs. 5, 6) of this species are very good ; 

 but figs. 1, 2, being drawn only half-size are apt to mislead unless care be 

 exercised. Especially is this the case with fig. 2, which is of course thinner than 

 an actual specimen of that diameter would be ; because the thickness of the shell 

 decreases proportionally from youth upwards, as may be learnt from figs. 3, 4, 

 which represent the young stage. Figs. 5, 6, although included in this species by 

 d'Orbigny, cannot be allowed to remain here, but probably belong to H. illustris 

 (p. 153). 



The figure 2 of Chapuis and Dewalque {loc. cit.) is of natural size, and repre- 

 sents a specimen without any of the senile — smooth — character. It is more 

 useful for obtaining a correct idea of the species than d'Orbigny' s figure, 

 and shows the characteristic spaces between the bunches of ribs. I cannot, 

 however, understand the extreme thinness of the front view (fig. 2 b). This does 

 not agree with my specimens, nor with d'Orbigny's, if his figure be enlarged twice 

 every way. 



The drawing of the species by Bayle under the name Hammatoceras Ogerieni 

 is of rare execution. The backward direction of the ribs is very apparent, but 

 not so the interspaces between the bunches; the ribs, too, appear thicker. 

 Apparently the condition of the specimen is excellent. 



Grottsche^ quotes a species from the Cordilleras of the Argentine Republic as 

 Harj). afE. A. variabilis ; but, as he gives no suture-line, it would not be safe to 

 venture an afiirmative opinion on the point. To find a species even of this genus 

 in so distant a locality would be very interesting. 



The grand specimen figured by Dr. Wright (op. cit., pi. Ixviii) conveys a good 

 idea of the variety a. 



When I selected this Ammonite to give its name to the Cotteswolds Sands 

 under the title Variabilis -suhzone I had included H. jugosa in this species. Now 

 that the separation of H. jugosa has been effected, the name Variabilis-suhzone is 

 not quite so appropriate, because the species is really rare. On the other hand, 

 the commoner H. jugosa cannot be considered to have been known, and could not 

 therefore have been used. 



Haugia variabilis occurs in the Cotteswold Sands at Coaley Wood (Bed 16) 

 and at North Nibley (Bed 30). Wright quotes his grand specimen from Nails- 

 worth. The species is very scarce. 



Plate XXV, fig. 2, represents a young example of the species. For a good 

 delineation of a grand adult specimen (var. a) I must refer the reader to Dr. 

 Wright's ' Monograph on Lias Ammonites,' pi. Ixviii. As neither this author nor 

 myself happen to have given a front view it should be remembered that the 



^ " Ueber jurassische Versteinerungen aus der argentinisclien Cordillere," ' PalsBontographica,' 

 Suppl. iii, Lief, ii, Heft 2, pi. i, fig. 9 ; Cassel, 1878. 



