Conchifera. J22 Exogyra. 



Boussingaultii, d'Orb. Am. Merid. 91, 18, 20. E., Fr., G., 



N. Grenada. N. 



bulla, Sow. G. T. vol. iv, pi. 2, f. 1. E. Weald. 



canaliculata, Sow. Sp. (Chama), Gabb, 1861. G., Fr., Sw., 



E. G., C. 



caprina, Con. (Arietina), Jour. Acad. 2d s. vol. ii, 273, 24, 3-4. 

 columba, Lam. Sp. (Gryphaea), Goldf. P. G. 34, 86, 9. E., 



Fr., G., Crimea, Portugal. U. G. 



conica, Sow. Sp. (Chama), Goldf. P. G. pi. 87, f. 1. Eng., 



Portugal, Sweden, Germany, Ireland, France. U. G. 



Couloni, Defr. Sp. (Gryphaea), d'Orb. Am. Merid. 93. Fr., 



G., Cr., N. Gren. N. 



costata, Say. 1821, Jour. Acad. 1st ser. vol. ii, p. 43. All of 



the United States except the Northwest. C. 



decussata, Goldf. (inflate), P. G. pi. 86, f. 11. 

 densata, Con. Lynch's Exped. 224, 18, f. 102 and 106. Syria. C. 

 flalellata, Goldf. (plicata), P. G. 38, 87, 6. 



fimbriata, Con. Proc. Acad. 1855, p. 269. Texas. C. 



foliacea, Con. per err. (fimbriata), Emory's Rep. pi. 7, f. 2. 

 fragosa, Con. 1855, Proc. Acad. p. 269. Texas. C. 



harpa, Goldf. (plicata), P. G. 38, 87, 7. 

 harpa, Leym. Roem. pars, not Goldf. (plicata). 

 inflata, Goldf. P. G. 121, 114, 8. G., India. C. 



haliotoidea, Sow. Sp. (Chama), Goldf. pi. 88, f. 1. E., G., 



Sw., Crimea. C., U. G. 



imbricata, Krauss. Nov. Act. C. L. C. vol. xx, 460, 50, 2. S. 



Africa. U. G. 



interrupta, Con. Jour. Acad. 2d s. vol. iii, 330, 34, 15. Miss. C. 

 laciniata, Nils. Sp. (Chama), Goldf. 35, 86, 12. Fr., G., Sw. C. 

 laevigata, Sow. (conica), M. Con. 605. 



autre c6te, si ces derniers offrent parfois et accidentellement un crochet tourne 

 exterieurement, c'est la une disposition purement accidentelle et facile d'ailleurs 

 si distinguer, par sa variabilite et son irregularite, de celle si reguliere, et si fon- 

 damentale qui caracterize les Exogyres." 



My own observation, true it has been on a much more limited scale than that 

 claimed above, accords with this in all but one individual instance. Morton's 

 type of Ostrea torosa is an E. costata, very much deformed and with almost paral- 

 lel sides, a true oyster in form, but the beak is imperfect, and were it present, 

 it might in its young state have shown a spiral tendency. There can be no doubt 

 of its being the common species of Exogyra of New Jersey, since it has the most 

 typical form of surface-markings and all the other characters. It is an unique 

 example, and being a monstrosity, can have no weight as testimony to conflict 

 with M. Leymerie's opinion. 



