Manchester Memoirs, Vol. lix. (191 5), No. 4. 



IV. Variation in a Carboniferous Brachiopod— 



Reticularia lineata (Martin). 



By Henry Day, B.Sc, 



Geological Department, The University, Manchester. 

 {Read November 3rd, 1914. Received for publication, December 22nd, IQ'4-) 



The shell dealt with in this paper is undoubtedly the 

 Conchy liolithus anomites (lineatus) of Martin, as it agrees 

 in every detail with his description and figure {Petrificata 

 Derbiensia, PL 36, Fig. 3). He speaks of it as " common 

 in limestone, particularly near Castleton," and it is of 

 interest to note that my own specimens came from the 

 same neighbourhood. 



Davidson ("British Fossil Brachiopoda," Vol. II., 

 Pt. V., p. 62) describes the species under " Spirifera 

 lineata, Martin," with a list of synonyms. He distinguishes 

 two principal varieties — lineata and elliptica, but on a 

 later page (p. 226) he expresses some doubt as to 

 .S. elliptica being correctly placed among the varieties of 

 lineata. . Davidson gives a reproduction, though not a 

 very accurate one, of Martin's original figure (op. cit.), and 

 in his description of the first variety {lineata) he considers 

 6". imbricata, Sow., *S, Martini, Fleming, and vS. reticulata, 

 McCoy, as synonymous with Martin's species, but certainly 

 the S. reticulata of McCoy, with its strong mesial sinus, 

 can scarcely be accepted as being the same species as 

 lineata. 



The specimens exhibit the reticulation of 5". lineata, 

 so well described by Davidson (op. cit., p. 225), and also 



jFebntary litJi, 1915- 



