Report of tee state Geologist, 



525 



ports but the median septum and the portions of the loon 

 attached t<> its anterior extremity. 



Fig. 178. — Krauaaina rubra, n, fora- 

 men: /(o, cardinal process: a, b, adduc- 

 tors: /», pallial sinuses: g, brachial sup- 

 ports; /, septum. (Davidson.) 



Fig. 174 — Magas pumihu. t>, 

 median septum; g\ brachial sup- 

 ports. (Davidson.) 



( )f Pala3ozoic genera Tropidoleptus alone has afforded evidence 

 of actual connection in the mature state of the descending lamellae 



Fig 175.— Bouchardia rosea, h, for- 

 amen; ab, adductors; e, diductors; A;, 

 cardinal process; g, brachial supports: 

 I, septum. 



Fig. 176. — Brachial valve of 

 Platydia anomioides. g, loop: I, 

 median septum. (Davidson.) 



with the median septum, a condition of the brachial apparatus 

 comparable to that of Platidia among living forms. 



In many of the terebratuloids the union 

 of the crura and primary lamellae is repre- 

 sented by sharp crural angles directed in- 

 wardly. In Liothyrina, which has the entire 

 supporting apparatus remarkably abbre- 

 viated, these angles are conspicuous, while 

 in Terebratulina they unite to form a con- 

 tinuous band. In the Devonian 

 STRiNGocEPffALus, the crura are very long, the 

 loop absent, and the lamella very broad and 

 situated iust within the margin of the brachial FlG - m - ~ Muscul *r and 



, p • i • j. ,.t brachial apparatus of String- 



valve; trom it extends a series oi filamentous ocephaius BwUni. a, ad- 

 processes, which are directed towards, and fetors: 6, diductors; c , car- 



r ' flinal process: d, brachial 



mav have been attached to the crura. support. (Hoernes.) 



77 



genus A'' 



