part 1] THROUGH THE A3FDES OF PERU AND BOLIVIA. 37 



PALiEONTOLOGICAL NOTES. 

 'CONULARIA AFRICANA Sliarpe. (PI. I, fig". 1.) 



This species, which was originally described by Sharpe from the Bokkeveld 

 Beds of South Africa, 1 is characterized by the fact that the interspaces between 

 the transverse ribs, in all states of preservation, are entirely devoid of any 

 longitudinal striatum.. The smooth and somewhat pronounced transverse ribs 

 are bent sharply towards the mouth, meeting along the median line on each 

 side of the pyramid at an angle of about 120°. One specimen was obtained 

 which showed that the ribbing is continued over the inner surface of the 

 incurved lobes of the aperture. 



This form has also been described from Bolivia by Ulrich. 2 



Conularia baini Ulrich. (PI. I. fig. 2.) 



Numerous examples of this species were obtained from the ferruginous 

 nodules in the upper shales of Taya Taya, the reticulate appearance of its 

 ornamentation readily distinguishing' it from C. africana, with which form it 

 has been confused by Knod. 3 



The transverse ribs, which curve towards the mouth and do not bear 

 tubercles, are extremely fine in the young- shell, but become coarser with in- 

 creased growth ; the somewhat sudden change is marked by the incoming of 

 longitudinal ornamentation in the form of subordinate, flattened or gently- 

 rounded ribs crossing the interspaces between the transverse ribs. The latter, 

 however, are uninterrupted, except along the median line of each pyramid face, 

 where a definite midrib occurs. 



The longitudinal ribs are most marked towards the angles of the shell, and 

 do not alternate in successive interspaces as in the North American form 

 C. huntiana Hall, 4 being arranged as a linear sequence, resembling in this 

 respect the type of ornament figured by Barrande as occurring in C. proteica? 

 G. baini was first described by Ulrich from Bolivia, 6 and was compared by 

 him with C. continent! var. rudis of Hall. 



The Peruvian shells, however, show no signs of interlocking of the trans- 

 verse ribs along the median line, a feature which appears to be characteristic 

 of Hall's species." 



Conularia quichua Ulrich. (PI. I, fig. 3.) 



This typical South American species is characterized by its distinctive 

 outline, and by the extremely fine nature of its ornament. The transverse ribs, 

 which curve gently towards the mouth and are cut by a shallow median 

 groove on each face, bear numerous small tubercles, due apparently to their 

 intersection with the faint longitudinal striation. By abrasion of these tubercles 

 each rib appears to be pierced by a single row of closely-set minute per- 

 forations. 



A cross-section of the shell has the form of an elongate oval, and though 

 this appears to be a constant feature, occurring both in our specimens and in 

 those obtained by Ulrich from Bolivia, 8 it may possibly be due to deformation, 

 consequent on the possession of an extremely thin shell which may have been 

 sufficiently flexible to resist the fracture that has affected many of the more 



1 Trans. Geol. Soc. ser. 2, vol. vii (1856) pi. xxvii, fig. 13. 



2 ' Palaozoische Versteinerungen aus Bolivien ' Neues Jahrb. Beilageband 

 viii (1892) p. 29 & pi. iii, fig. 4. 



8 ' Devonische Faunen Boliviens ' Neues Jahrb. Beilageband xxv (1908) 

 p. 516 &pl. xxiii, fig. 8. 



4 'Natural History of New York: pt. vi, Palaeontology' vol. iii (1861) 

 pi. lxxii a, figs. 2 a & 2 b. 



5 ' Systeme Silurien de la Boheme ' vol. iii (1867), Ptoropodes, pi. v, fig. 18. 



6 Op. supra cit. p. 36 & pi. iii, fig. 8. 



' ' Nat, Hist. N.Y.— Pal.' vol. v, pt. ii (1879) pi. xxxiv a, figs. 7 & 8. 

 8 Op. supra cit. p. 34 & pi. iii, figs, la & 7 6. 



