APPENDIX. 9 



oral arms disposed in about six close whirls, their cavities opening into the prolongation of the visceral 

 sheath in front of the adductors. 1 



" Observations on the living Lingula are much wanted ; the oral arms probably extended as far as the 

 margins of the shell ; and the pedicle, which is often nine inches long in preserved specimens, is doubtless 

 much longer and contractile when alive. The shell is horny and flexible, and always of a greenish 

 colour." 



Mr. Salter has found that Lingula Davisii from the Lower Silurian of Tremadoc, has a pedicle 

 groove, like Obolus, and that it might, perhaps, form a distinct section of Lingula. This will, however, 

 require some further investigation. 



Page 135. 



In Obolus the hinge-margin is thickened inside, and slightly grooved in the ventral valve : posterior 

 adductor (a) impressions separate : anterior pair (c) sub-central : impressions of sliding muscles (b) lateral, 

 as shown by my woodcuts (p. 136). The pedicle scar in the centre of woodcut, fig. 54, has no letter. 



Page 136. 

 Woodcut, fig. 51, for "from Ruma," read "from Russia." 



PART I. 



BRITISH TERTIARY BRACHIOPODA. 



Since the publication of this Monograph, in 1852, no new species seems to have been discovered, hut 

 I am able to offer a few additional illustrations from more perfect individuals. 



Page 5. 



Lingula Dumortieri has been erroneously spelt Dumowtieri, in pp. 4, 5, 6, and 9, (Mr. R. Ch. Dewael 

 has defined the stratigraphical position of this species in the Antwerp Crag. ' Bull. Acad. Royal.' 

 Belgium, 1853.) 



1 In p. 211, Mr. Woodward adds several interesting comparisons between the dispositions of the 

 animal in Lingula and the other genera, and from which I have transcribed the following passages : 



" On separating the valves of a recent Terebratula, the digestive organs and muscles are seen to occupy 

 only a very small space near the beak of the shell, partitioned off from the general cavity by a strong- 

 membrane, in the centre of which is placed the animal's mouth. The large cavity is occupied by the fringed 



arms Their nature will be better understood by comparing them with the lips and labial tentacles 



of the ordinary bivalves; they are, in fact, lateral prolongations of the lips, supported on muscular stalks, 

 and are so long as to require being folded or coiled up. In Rhynchonella and Lingula the arms are spiral and 

 separate : in Terebratula and Discina they are only spiral at the tips, and are united together by a membrane, 



so as to form a lobed disk The mouth conducts by a narrow oesophagus to a simple stomach, which 



is surrounded by the large and granulated liver : the intestine of Lingula is reflected dorsally, slightly 

 convoluted, and terminates between the mantle lobes on the right side. In Discina it is reflected vertically, 

 and passes straight to the right, ending as in Lingula. In Terebratula, Rhynchonella, and probably all the 

 normal Brachiopoda, the intestine is simple and reflected ventrally, passing through a notch or foramen in 

 the hinge-plate, and ending behind the ventral insertion of the adductor muscle." 



2 



