BIBLIOGRAPHY OF PALAEOZOIC CRUPTACEA 111 



ULRICH (E. O.) and BASSLER (Ray S.) — Continued 



The valves are usually short, semi-elliptical in outline, and sharply lobed. 



Group Beyrichia Bucliiana: 



The anterior and median lobes are joined, but the anterior lobe is thinner and the 

 ventral connection proportionally thicker than usual, the combitiaiion giving to the 

 united lobes a striking simiiarily to tlie liorseslioe ridge in the H. luii^ula section of 

 Boliia. 



Group Beyrichia tuber cuhita: 



This section comprises a number of species, in vvhicii the anlerioi' aiui posterior lobes 

 are broken up by minor furrows — the posterior lobe into 2, tlie anterior lobe into from 

 2 to 6 or 7 node-like parts. Beyrichia Buchiann-liihcrculata Reuter, would represent 

 about tlie simplest t\pe, and B. pitstitlosa Hall and B. Xoclli/ii^i Reuter the most complex. 



Group Beyrichia Salteriana: 



The species of this group are not as large as those of the preceding groups and 

 differ in tlie fullness of their lobes and proportionate narrowness of the furrows. 



Group Beyrichia clavata: 



The small group includes B. Jnnesii Boll, and possibiv B. umhnnata Reuter. 



Subgenus Stcuslojfia, new. 



Group Beyrichia Linnarssoni: 



This group includes B. aniiqua, B. acuta, B. simplex, li. Lirinars.snni, B. sii^nala, B. 

 heyrichiodes and probably B. crratira Krause. 



Group Beyrichia intern/ pta : 



The illustrations given by the authors show possible derivation of the B. inlerrupta 

 group from Euryohilina, and its relations to Beyrichia clavata group and to Steusloffia. 



The autliors place under Kloedenia the following species: 



Khedeiiia apiciilata Jones, A'. Barrctti (Beyrichia Barrett! W'el.), A', ceriticnriiis n. 

 sp.. A', concin/ia (Beyrichia cmiciniia J. tV H.), A', funhriata n. sp.. A', ^raniilata 

 (Beyrichia i^raiiulata Hall), A. i/iilialis (Beyrichia initialis I'lricli), A', intermedia (B. 

 intermedia J. & H.), K. intermedia marginata \. k H., A', jerseyensis (Beyrichia jer- 

 seyensis Weller), K. Kummeli (Beyrichia Ktunmeli W'eller), K. manliensis (Beyrichia 

 manliensis Wei., K. manliensis deckerensis (Beyrichia deckerensis Weller), K. marj^in- 

 alis n. sp., A', montavuensis (Beyrichia momtai^uensis Wei.), K. nearpassi (Beyrichia 

 nearpassi ^^'eller), A. octtlina (Beyrichia oculina Hall), A', parasitica (Beyrichia par- 

 asitica Hall), A', praenunlica n. sp., A', pinictillosa n. sp.. A'. retHera n. sp., A', scniica 

 (Beyrichia Klncdeni var. scotica J. &: H.), A', simplex Jones. A'. Smocki (Beyrichia 

 Smncki Weller), K. sussexensis (B. siissexeniis Weller), A', tnhercnlata (Beyrichia 

 tuherculala Salter), A', -icall packensis (Beyrichia ^vallpackensis Weller), A'. If'ilcken- 

 sianna (Beyrichia Jf'ilckensianna Jones), A'. If'ilckensianna plicala (Beyrichia H'ilck- 

 ensianna plicata Jones). 



(^f the above species A. niitalis and A', praenuniia are Middle Ordovian and A. 

 simplex late Devonian. All tlie others Silurian. 



Tlie genus Kvammodes Jones is closely allied, distinguished chief1\' by the iiuich 

 greater ine(|uality of its vahes, the thick ventral edge of the right overlapping the 

 smaller left valve. There are some peculiar differences in lobation also. 



Tetradella Genotype T. f/uadrilirata H. & W. 



List of Ordovician species: 



Tetradella f affinis (Beyrichia affinis Jones), T. hohemica (Beyrichia hohemica Barr. 

 MSS. Jones), T. hussacensis (B. hnssacensis Jones), T. earinata (B. carinata Krause), 

 T. complicata (B. com plicata Salter), T. com plicata decorata (Beyrichia com plicata 

 var. decorata Jones), T. ? digitata (Beyrichia digitata Krause), T. / digilata separata 

 (Beyrichia digitata var. separata Sfeusloff), T. (Kieso-zvia) dissecta (Beyrichia dissecta 

 Krause), T. f crratica (Beyrichia erratica Krause), T. harpa (B. harpa Krause), T. / 



