HAUGIA JUGOSA. 149 



aperture of this species is thicker and more quadrangular, more especially when 

 immature, than that of H. jiigosa. 



Haugta JUGOSA (Soiverby). Plate XXIII, figs. 11—15^ (not 16, 17) ; Plate XXIV, 



Plate XXV, fig. 1 ; Plate XXVI, fig. 6 ; Plate 

 XXVIII, figs. 1—3 ; Plate A, fig. 35. 



1815. Ammonites jugosus, Sotverby. Mineral Conchology, pi. xcii, fig. 1. 



1874. — Ogeeieni, Dumortier. Etudes pal. Bassin Ehone, iv, pi. xix, 



figs. 3, 4. 



1882. Haepoceeas vaeiabile, Wright {non d'Orbigny). Lias Amm. ; Pal. Soc, 



pi. Ixvii, figs. 1 & 2, only.- 



1885. Hammatoceeas [Sonninia] Ogeeieni, Haug. Beitrilge Monogr. Harpo- 



ceras ; Neues Jahrbuch fur Mine- 

 ralogie, iii Beil.-Bd., p. 658. 



1885. Haepoceeas vaeiabile, Quensfedt. Amm. Schwabischen Jura, pi. Iii, 



fig. 11 (12 ?), not 13. 



Discoidal, compressed, hollow -carinate. Whorls flattened, very little convex, 

 ornamented when immature with very regular arcuate ribs, which, rising in twos 

 and threes from small tubercles on the inner margin, cross the lateral area, and 

 bend slightly forwards on the ventral area. Ventral area very narrow, carrying a 

 fairly large hollow carina. Inner margin convex, smooth. Termination (Plate 

 XXVI, fig. 6) a subsigmoidal bend with long outer arc not greatly projected on 

 the ventral area. 



When I wrote the explanation of Plate XXIII I had mistaken Dumortier's 

 Am. Ogerieni. In consequence, I described certain specimens (figs. 11 — 15) 

 under the name " variahilis." Just before the issue of Part III, but too late to 

 make any alteration, I discovered my error. In order to be quite sure I wrote to 

 my friend Dr. Haug upon the subject. He informed me that he had no doubt of 

 the identitj o^ Haugia jiigosa (as figured in my Plate XXIII, figs. 11, 12) with 

 Am. Ogerieni, and he also considered that the species should be called by 

 Sowerby's name on account of the law of priority. 



Dumortier points out the difference between his species and H. variabilis very 

 clearly. He says (p. 79) " LM. Ogerieni se distingue . . . de VA. variahilit; 

 par ses tours plus renfles, la regularite et la direction de ses cotes, sa carene moins 



^ Alter description of PI. XXIII, figs. 11 — 15, in accordance with this. Erase in explanation of 

 fig. 11 from " But as neither" to end of sentence. 



^ If the backward direction of the ribs be correct, the specimen here delineated is a form exactly 

 intermediate between Haugia variabilis and this species. 



