PLATE XXIV 



BRACHIA (Page 293) 



Figure 1. — Brachial supports of Macandrevia cranium Miiller; nearly 

 adult; p,p, points of former attachment to a septum in terehrataliform 

 stage. Enlarged. 



Figure 2. — Dorsal valve of Terehratulina septenlrionalis Couthouy, 

 ■with cirrated brachia attached ; showing relations of calcareous loop, 

 which is darkly shaded in the drawing. 



Figure 3. — Dorsal valve of Magellania herguelenensis Davidson, with 

 cirrated brachia attached ; showing relations of calcareous loop, which is 

 darkly shaded in the drawing. 



TEREBRATALIA OBSOLETA Dall (Pages 406-408) 



Figure 4. — Loop in late platidiform stage, with cirrated margin of 

 lophophore attached. X 15. 



Figure 5. — Side view of lower half of preceding ; showing cirrated 

 edge of lophophore passing from the descending branch of loop to sep- 

 tum, and over ascending branch. X 15. 



Figure 6. — Dorsal view of adult shell. Natural size. 



Figure 7. — Exterior of ventral valve. Natural size. 



Figure 8. — Profile ; showing relative convexity of valves. Natural 

 size. 



Figure 9. — Front view. Natural size. 



Figure 10. — Early larval brachiopod ; interior of dorsal valve ; show- 

 ing the incomplete circlet of tentacles or cirri, visceral mass, and some of 

 the muscles ; (i, li', first tentacles developed ; a, ti', second pair of ten- 

 tacles ; (3, t3', third pair of tentacles; U, W, last pair; ti, new tentacle 

 just growing on one side of median line ; m, mouth ; ds, dental sockets ; 

 did, diductor muscles ; ad, adductor muscles. X 90. 



Figures 10, 11, 12, are drawn from specimens which had been dried 

 and afterward expanded by soaking in water, and then stained and pre- 

 pared for mounting. The original proportions and relations of parts 

 may be therefore somewhat altered. 



Figure 11. — Gwyniform stage ; showing complete circle of cirri ; ps, 

 pallial sinus ; se, setie in edge of shrunken mantle. X 60. 



Figure 12. — Cistelliform stage; showing deflection of growing cir- 

 rated edge of lophophore by dorsal septum (s) ; m, mouth ; ad, adductor 

 muscles ; did, diductor muscles ; ds, dental sockets. X 60. 



