part 2] SYIUXGOTHYRIS AND SPIHIFEHIXA. 189 



majority of which possessed a syrinx while a few did not, is some- 

 what remarkable. 



So far as I am aware, no shells referable to the genus have 

 been found in the Carboniferous Limestone of Great Britain and 

 Ireland. ■ 



Type-species. — Pseudosyrinx s~ampsoni (Weller). Illinois 

 Geol. Surv. Monogr. 1 (1914) pp. 105-406 & pi. Ixvii, figs. 11-13; 

 Syringotliyris sampsoni Weller, Bull. Geol. !Soc. Am. vol. xx (1909) 

 p. 311 & pi. xiv, fig. 4. 



The prevailing septal arrangement in the pedicle-valve of forms 

 with a plicated fold and sinus is that described as existing in 

 Sp. duplicicosta (see fig. 1 i, p. 100), but E. M. Kindle has 

 described a curious modification of the septa in certain Devonian 

 fossils, for which he established the genus Syringospira. 



Syiunqospira Kindle. 



'The Devonian Fauna of the Ouray Limestone' Bull. U.S. Geol. Surv. 391 (1909) 

 pp. 28-29. 



The genus was established for shells in which the pedicle-valve 

 is pyramidal and the area flat, as in S. cuspidata. The author in 

 describing the genus says : ' though somewhat closely related to 

 Syringotliyris, it represents a type generically distinct from it ' ; 

 actually, however, it resembles Syringotliyris in nothing but its 

 pyramidal shape. 



Type-species. — S. prima Kindle, op. cit. pp. 29-30 & pi. vii, 

 figs. 8-8 d ; pi. viii, figs. 1-1 a. This is the only species at 

 present referred to the genus, and only two specimens were known 

 to the author when the name was proposed. 



Horizon and locality, — The (Devonian) Ouray Limestone, 

 Hillsboro' (New Mexico). 



S. prima differs from Syringotliyris in the following respects : — 



(1) The whole surface of the shell, including' the fold and sinus, is 

 plicated, and the ribs are much more numerous than in any species of 

 Syringotliyris. 



(2) The septal system in the pedicle-valve consists of a small transverse 

 plate joining the delthyrial supporting-plates a little below the level of the 

 area. The delthyrial supporting-plates do not extend to the floor of the 

 valve, but curve towards one another and unite in the median line (see 

 fig.^P- 166). fJt 



(3) The shell-substance is impunctate, and the whole area is marked by 

 vertical striations. 



III. Notes upon Certain Species incorrectly referred to 



SyMWGOTHYEIS, AND UPON SPECIES OF SyRINGOTHYTHS 



supposed to possess plications upon the fold and 

 Sinus. — The Genus Syiungopleuka. 



Spirifer distqns Sowerby, a species in which costae occur on the 

 fold and sinus as well as on the lateral slopes of the shell, has 

 been referred to Syringothyris; Spirifer alius Hall (Middle 

 Devonian), with similar external characters, has been regarded as 



