Reviews — T/ie Attachment of Brachiopods. 427 



coquilles de quelques Strophoincnacea''^ (Bull. Com. geol., 1907, 

 Tol. xxvi, pp. 181-201) are also applicable to the Spiriferacea aud 

 Terehratulacea. Some of the conclusions arrived at are given herewith. 



The attachment of Brachiopods gives rise to alteration in. the 

 shape of the shell. Considerable difference may occur in this respect 

 between neighbouring individuals dependent upon the relative 

 conditions of attachment of each individual. Distinctions of shape 

 in the shell arising from such a cause cannot, however, be considered 

 as even of varietal value. The Devonian Spirifer verneuili, Murch., 

 and Sp. rugulatus, Kutorg., each affords instances of great variability 

 within the limits of the species, and many of these variations have 

 given rise to new specific designations. The development of the 

 ear-like extensions is affected by the nature of the attachment, but 

 the usually curved condition of the areal surface depends upon the 

 straightness of the hinge-margin, and not upon the attachment of 

 the areal portion to an underlying body. In certain cases the change 

 undergone by the members of the Spiriferacea consequent upon the 

 attachment has given rise to so-called generic differences as in the 

 case of Cyrtia and Cijrtina. 



The type of the genus Cyrtia {Cyrtia exporrecta, Dalm.) is 

 synonymous with Spirifer plicatellus,?in examination of the Stockholm 

 Museum collection of Silurian fossils from Gottland having shown 

 that the distinguishing feature (the presence in Cyrtia of a pedicle 

 opening in the pseudodeltidium) is inconstant. In fact, Cyrtia 

 exporrecta represents individuals of Spirifer plicatellus differing 

 primarily in the growth of an elevated area, and the correlative 

 appearance of a circular opening in the pseudodeltidium. The 

 Devonian Cyrtia tmirchisoniana represents a group which undoubtedly 

 belongs to one species, while the relationship of Cyrtina heteroclyta 

 and Spirifer elegans is considered to be analogous to that between 

 Cyrtia exporrecta and Spirifer plicatellus. The Spiriferacea of the 

 Alpine Trias present peculiar difficulties, and it is doubtful in many 

 cases whether we have to do with Spiriferince or Cyrtina;. The 

 author differs from Bittner and Zugmayer in the latitude allowed 

 in the interpretation of several species. The Upper Palaeozoic 

 Ctjrtitice, like the Triassic, are held to be traceable from Spiriferina. 

 Cyrtina carhonaria^ McCoy, is shown to possess a plate adjacent to 

 the spondylium, which plate is considered by the author to correspond 

 to a pseudodeltidium. A similar feature is proved to exist in 

 Spiriferina suessi. Attachment is also considered in its bearing 

 upon the convergence characters of Brachiopod development. The 

 fixation is found to have a relationship not only to the development 

 of a high area and a pseudodeltidium but also to that of a spondylium. 

 Terehratula, Trigonosemus, and Terehrirostra are treated from the 

 same standpoint. In agreement with Davidson Cistella neapolitana 

 and C. hiplicata are considered synonymous, the differences between 

 the two being occasioned by the nature of attachment. In the latter 

 part of the article attention is drawn to the occurrence in certain 

 districts of several Brachiopod types characterized by elongation of 

 the ventral valves. Thus there occur in the Permo-Carhoniferous 

 of the Donjetz Basin elongated Spiriferina and Meekella, and Spirifer 



