URACUIOrOOA. 10!) 



li. MoHHISIA ? EU8TICTA. 



Sfi)'ll siniill, orbicular, (U-prcssed. smootli, witli a fow obscure 

 Hues of {i;n)\vtji. diMiscly i)uuctatc aud onianniitid witli radiatiu}^ 

 rows of uiiiiutf ]>i)iuts ; dorsal valve convex, with an obtuse lon- 

 gitudinal rid},'e ; beak not nrouiiueut ; fonuueu large, iucouiplote ; 

 (ieititUuui rudiuicutary. Lou. 54, lat. 5 lines. 



Terebralula enstieta, P/iilippi, IS.'Jfi, Moll. Sicil. i. p. 98. t. 6. f. 9. 

 Orthis eustieta, Phil. ISI-J, Moll. Sivil. ii. p. /<>. 

 Fossil. Pliocene. Palermo. 



10. KRAUSSIA. 



Shell snbcircular, witb a nearly straigbt hinge-line ; beak 

 truncated ; forauieu large and round ; deltidia small, disiuiited ; 

 beak laterally keeled ; huige-area Hat ; dorsal valve longitudinally 

 depressed ; internal skeleton consisting of a small forked pro- 

 cess arismg from the septum, near the centre of the valve (tig. 19). 



Kraussia (rubra), Daindson, 1852, Ann. Nat. Hist. p. 3G9. 

 Terebratulai aunulifer;e (part.), Qitenst. Handb. p. 4()3. 



Fig. 19. Kraussia rubra. Fig. 20. K. Lamarckiana. 



1 



\ 



A 



Fip. 19. — Interior of dorsal valve, showing the forked apophysis in the centre, 

 and the branching pallial vessels on each side. 



Fig. 20. — Interior of dorsal valve with the animal, from a dry specimen in the 

 British Museum. 



The brachial apparatus of Kraussia Lamarckiana (fig. 20) is 

 like' that of Terebratula and Terebratella, but the arms are un- 

 usually small in the species examined, and their fringes do not 

 extend more than half way towards the border of the shell ; 

 they are supported solely by the small forked process above 

 described, no other part of the apophysary system being calcified. 



1. Kkaussia rubra. B.M. 



Shell suborl)icular, ornamented with numerous, radiating ribs, 

 sometimes bifurcating, or augmenting by intercalation ; colour 

 pale, with red rays and bands of growth ; dorsal valve (see fig. 19) 

 slightly depressed in the centre, in front, furnished internally with 



