28 



PALJCOXTOLOGV OF NFW YORK. 



termineJ, but we have evidence that the outer or epidermal layer is more 

 largely corneous than those within, and, so far at least, its structure is in 

 harmony with that of Limiula, as demonstrated by Gratiolet. But on the 

 other hand, the relative amount of mineral matter in the shell is far in excess 

 of that in Lingula, and its structure in this respect is wholly in consonance with 

 the other features which establish- its transitional position in the line of de- 

 velopment from Lingula to Trimerella. In the latter genus and its associates, 

 the heavy shells have been rarely preserved, or when preserved, their original 

 structure is so essentially altered by dolomitization and crystallization, that it is 

 impossible to gain an accurate conception of their composition. Undoubtedly 

 they were substantially calcareous, with small percentages of organic matter, the 

 latter perhaps relatively increased in the thinner-shelled forms, like Dinobolus and 

 some species of Monomerella. The evidence at hand would lead to the presump- 

 tion that the loss of the organic constituents of the shell, and the increase 

 in calcareous matter, progressed jsar/ /ja^su with the assumption of Trimerelloid 

 characters. 



Genus LAKHMINA, (Ehlert.* 1887. 



1885. DaHdxonelUifVI AAGBH. Mem. Geol. Siii-v. India ; Palasontologia Indica, Ser.XUI, l,iv, I'use.r), p.762. 



Not DavidmmeUa, Mcnibr-Chalma.s, 1880. Bull. Society Gt'ologique <ie France. 

 1887. LMklimina, (Rn\,KV.T. Fischer's Manuel de Conchyliologie ; Brachiopodes, p. I'iOS. 



This genus is defined by Dr. Waagen in essentially the following terms: 

 General outline more or less linguloid. 

 The ventral valve is the larger am 

 possesses a prominent ape.K, which is 

 provided, on its lower surface, with a 

 deep furrow lor the pedicle. In the in- 

 terior of the ventral valve, the cardinal 

 margin is somewhat thickened, without 



... Daridsonella (=Lakhmina) UnguloUles, alter VVaagen. 



forming a distinct area. Below this f'o. is. rciiiciovaive. fio. m. Brachial vaivc. 



» In tlie |.reiiaiati< f the .liticnssion of lliis (,r,.,„i.s. and generally throuifhiiut the volume, the term 



DAVID.SONBLLA had l)een adojited, not beinj,' aware that the name liad been used by Munier-Chalmas in 1880 

 for a penus of Lia;;.'.ic brachiopods allied to Thbcidu-.m. We are therefore reluctantly compelled to adopt the 

 tei-m I.AKHMI.NA, proposed by CEiilert; thoujrh it must not be forgotten that it i.s to Dr. WAAfiK.v we are 

 indebted for the cai-eful analysis of the genus. 



