2. SOME CORRELATIONS OF ONTOGENY AND 

 PHYLOGENY IN THE BRACHIOPODA* 



(Plate XIII) 



The parallelism between the ontogeny and phylogeny in 

 the Brachiopoda has been worked out in numerous instances, j 

 To illustrate these, some more or less familiar genera may be 

 taken as characteristic examples. 



Li)tgula has been shown l)y Hall and Clarke QPal. N. K, 

 vol. viii, 1892) to have had its inception in the Ordovician. 

 In the ontogeny of both recent and fossil forms, the first 

 shelled stage has a straight hinge-line, nearly equal in length 

 to the width of the shell. This stage may be correlated 

 with the more ancient genus Faterina [= IpMdea], from the 

 lowest Cambrian. Subsequent growth produces a form re- 

 sembling Oholella^ a Cambrian and Lower Silurian genus. 

 Then the linguloid type of structure appears at an adolescent 

 period, and is completed at maturity. Thus Lingnla has 

 ontogenetic stages corresponding to (1) Paterina [= IpMdea]^ 

 (2) Obolella, and (3) Lingula, of \>^hich the first two occur as 



* American Naturalist, XXVII, 599-604, pi. xv, 1893. 



t C. E. Beecher. Development of the Brachiopoda. Part I. Introduction. 

 Amer. Jour. Set., XLI, April, 1891. 



Development of the Brachiopoda. Part II. Classification of the Stages 



of Growth and Decline. Amer. Jour. Sri., XLIV, August, 1892. 



Development of Bilohites. Amer. Jour. Sci., XLII, July, 1891. 



Revision of the Families of Loop-hearing Brachiopoda. Trans. Conn. 



Acad. Sci., IX, May, 189.3. 



Deslongchamps, E. Etudes critifjues sur des Brachiopodes nouvcaux on pen 

 connus, 1884. 



Fischer and (Ehlert. Brachiopodes : Mission Scientifique du Cap Horn, 

 1882-1883. Bull. Soc. Hist. Nat. d'Autun, V, 1892. 



