THE BEACHIOPODA. 51 



line. Its beak is sharp and much produced over the 

 smaller valve. As I cannot find that it has been figured before, 

 I ventured to name it Rhynchonella bilobata, n.sp. The first 

 specimen was found by myself at Bradford Abbas, in December, 

 1880. 



58. EHYNCHOXELLA BENECKEI, Haas. 



1881. RIIYNCHONELLA BEXECKEi, Haas, d. Brach. d. Juraf., v. 

 Elsass-Lothringen, plate iv., figures 3, 

 6-8 (1, 2, 4, 5). 



Dr. Haas quotes this species from the middle Lias, or what he 

 calls the costatusschichten, which he places just above the 

 margaritatusschichten. From blocks of stone in the Yeovil sands 

 (zone of Lytoceras jurense), I have obtained several specimens 

 which agree exactly in all respects with the figures (3, and 6-8) 

 given by Dr. Haas, of Rhynch. Beneckei. Specimens agreeing with 

 figures 1, 2, 4, and 5, I have, however, not seen, and therefore 

 have put them into brackets in quoting it. Dr. Haas, however, 

 takes as his typical examples of his species, figures 3 and 7, with 

 both of which our specimens agree exactly. 



The specimens from this district possess two, three, and four 

 ribs on the mesial fold, and the height of them varies consider- 

 ably. In young specimens the ribs are flat in proportion, and 

 increase in height faster than the shell grows in size, but in 

 specimens of the same size the height of the ribs is often 

 variable. 



This species is as it were between Rhynch. cynocephala, Eich., 

 and Rhynch. sulangulata, Dav., but in general the mesial fold is 

 not so raised as in either of them. Its ribs also do not extend 

 more than half way up from the base of the shell. As far as 

 I have been able to observe the . deltidial plates of Rhynch. 

 cynocephala are far larger in proportion than those of Rynch. 

 Beneckei. The far greater number of ribs, continued too, all up 

 to the beak, distinguish Rhynch. sulangulata from this species. 



Localities. Bradford Abbas (Dorset). I know of it nowhere 





