CAMBRIAN BRACHIOPODA — WALCOTT 75 



as smooth areas outside the crescent. Dr. CEhlert [1887, p. 1265] 

 says also that Lakhmina has "a straight and projecting beak per- 

 forated for the passage of the foramen,'' and reproduces Dr. 

 Waagen's figures showing a deep pedicle furrow. Only one shell 

 shows the apex of the ventral valve and the small false area beneath, 

 and one other' of the interior shows the true area and a triangular 

 depressed spot at the center. A fracture at the center has broken 

 out a bit of the shell, which gives rise to the narrow, deep furrow 

 described by Waagen. The ventral valve has a false area beneath 

 the apex ; a true area on a plane with the margins of the valve. 



When looking over the types of Neohohis and Lakhmina for the 

 purpose of having illustrations made of them, I noted that there was 

 a strong resemblance between the shells of the two genera; but, 

 having the impression that the ventral valve of Lakhmina had a 

 pedicle opening at the apex, drawings were arranged on the plates 

 under the conception that Lakhmina belonged with the Neotremata. 

 Dr. Charles Schuchert noted the same resemblance when looking 

 over the plates of this monograph and called my attention to it. I 

 then made a careful study of all of the specimens, and by the use 

 of acid developed several interiors of dorsal valves. I found that 

 the supposed perforation of the apex of the ventral valve of Lakh- 

 mina was the result of the breaking out of the minute apex; that 

 the dorsal valve of Neoholus zvarthi was the same as the dorsal valve 

 of Laklunina lingnloidcs, and that two genera and four species had 

 been based on specimens of Neoholus zvarfhi. 



The external characters of all of the shells referred to Neoholus 

 and Lakhmina are the same. Only one specimen of the interior of 

 the ventral valve that shows anything of the platform beneath the 

 visceral area occurs in the collections ; this was referred to Lakhmina 

 by Waagen, but the accompanying dorsal valves were first described 

 as Neoholus. By comparing the illustrations of Waagen [1891, 

 pi. 11], the student will notice that figure 8c of the interior of the 

 dorsal valve of Neoholus is essentially the same as the interior of 

 the dorsal valve of Lakhi'iijia, figure 4c, with the exception of the 

 thickened platform. 



It may seem as though it were forcing unlike forms into one 

 species to place all these specimens together, but with our present 

 information it appears to be necessary to do so. 



All authors have classified the shells described as Lakhmina with 

 Trimerella linguloides, and Hall and Clarke [1892&, p. 29] state that 

 in the present condition of knowledge it must be regarded as the 

 earliest representative of the Trimerelloid brachiopods. The ex- 



