DE. T. DAVIDSON ON RECENT BRACHIOPODA. 



malacologists and palaeontologists, I have considered the interior skeleton that supports 

 the labial appendages as a classiflcatory character that could be advantageously made 

 use of, and have consequently grouped the recent species into the two great divisions 

 Arthropomata, Owen { = Clistenterata, King), and Lyopomata, Ovfen {^= Tretenterata, 

 King), and into six families, as follows : 



Akthropomata., Owen= Clistenterata, King. 



1st Family 

 TEREBEA- 

 TULIDJE. 



Subfamily TerebratulinjK 



I. Genus Lioihyris, Douville 



II. Subgenus Terebratidina, d'Orbigny 

 III. Genus Waldheimia, King 



Subfamily Teeebrateixin^ 



Subfamily Megerlin^ 



Subfamily Magasin^ 



Subfamily Kraussinin^ . . . 



IV. Genus Terehratella, d'Orbigny 

 V. Subgenus MagaseJla, Dall. . . . 



VI. Genus Megerlia, King 



VII. Subgenus Laqueus, Dall . . . 



VIII. Genus Bouchardia, Davidson 



Subfamily AEGiopiNiE 



IX. Genus Kraussina, Davidson. 



X. Subgenus Mer/erlina, Deslongchamps. 



XI. Genus Arriio]ie, Deslongchamps .... 



XII. Subgenus Cistella, Gray 



2? 

 1 



L 



Subfamily not yet determined. 



2nd Family THECIDIID.E 



XIII. ? Giuynia, King . . 



XIV. Genus Platydia, Costa .... 



XV. Genus TheckUum, Defiance 



.) J T^ 1 T>TT1'^^T/-,TTf^-lTT^TTTT. TT. f XVI. Geuus Rhytichonella, FischeT 



3rd Family EHl NCHOXELLID^ i , ^ 



I XVII. Subgenus Atrctia, Jeffreys . . 



Jeffreys 



Lyopomata, Owen=: Treienterata, King. 



4th Family CRANIID.^ XVIII. Genus Crania, Retzius . 



5th Family DISCINID^ 



{XIX. Genus Discina, Lamarck . 

 XX. Subgenus Discinisca, Dall 



6th FamUy LINGULID^ | ^^^- ^'""' ^'"5'"^«' Bruguiere 



I XXII. Subgenus Olottidia, Dall . 



In 1884, M. E. E. Deslongchamps proposed a new scheme of classification for the 

 Terebratulidse, in which he objected to any arrangement based on either the extci-ior 

 shape of the shell or of the supports of the labial appendage. 



His first group includes the different forms in which the calcified brachial apparatus 

 or loop does not undergo any important modifications from its first origin up to the 

 adult condition. To the characters drawn from the brachial apparatus or loop is added 

 tliat of the presence of spicula, more or less complicated, which occupy in the mantle 

 all the parts connected with the organs of circulation (arteries, veins or veiny sinuses, 

 &c.), the labial appendages and cirri whicli accompany them. In this group he places 

 the recent genera Liothyris, TerebratuUna, ^legerlia, Kraussina, and FlatycUa. 



