BRACHIOPODA. 



335 



Genus ETHERIDGINA, (Ehlert. 1887. 



1876. Productiis, Etheridck, jr. Quart. Journ. Geol. Society, vol. xxxii, p. 4r)-l, pi. xxiv, ti^'-s. 1-14; 



pi. XXV, figs. 15-24. 

 1878. Prodiictus, ETHKRiDciS, .ir. Quart. Journ. Geol. Society, vol. xxxiv, p. 498. 

 1880. Productiis, D.wid.son. Monogfr. British Carb. Bracli. Suppl., p. 803, pi. xxxv, tigs. 4-13. 

 1887. Elherldqina, CEhlkrt. In Fi,scher'.s Manuel de Conchyliolojjie ; Brachioiiodes, j). 1278. 



Diagnosis. " Shell of very small size, nearly as broad as long, attached to 

 foreign bodies by the .spines of the ventral valve ; cardinal line straight, nearly 

 equaling the greatest width of the shell ; pallial outline semicircular ; ventral 

 valve with a small, entire [?] beak ; surface ornamented by concentric flexuous 

 plications, bearing a few scattered spines; cardinal process quadrifid." — 

 CEhlert, ut. cit. 



Type, Produdus compledens, Etheridge, Jr. 



Figs. 34-37. Productus [Etheridgina) complertens, Ktheridge. 



After ETHliRIDGE. 



Observations. This shell was admirably described by Mr. Etheridge in his 

 paper on " An Adherent Form of Productus" (1876) and presents the interest- 

 ing combination of distinctive productoid characters (absence of cardinal area, 

 hinge, etc.), with a mode of growth characterizing the genus Strophalosia. 

 The very small shells of this genus, which is thus far represented by the type 

 species only, have been found adhering to crinoid columns and fragments of 

 bryozoa ; that is, to surfaces of little expansion ; hence the creeping spines 

 appear to effect an attachment by encircling or hugging their host. This ap- 

 pearance is somewhat deceptive ; the surface of the pedicle-valve is itself 

 adherent, and the mode of growth of both shell and spines the same as that 

 already observed in some of the small species of Strophalosia {S. radicans, 



