146 MR. R. OWEN ON THE ANATOMY OF THE BRACHIOPODA. 
simillima). He enumerates three pairs of muscles belonging to the shell, and notices 
the situation of the mouth and stomach, but not that of the anus. The cloak, probably 
from its close adherence to the valves, he calls periosteum. 
Another account of the organization of Terebratula is given by M. de Blainville in 
the ‘ Dictionnaire des Sciences Naturelles’!. After noticing the symmetrical character 
of the soft parts, and their general relation to the valves, he proceeds to speak of the 
arms, and, preferring the opinion of Pallas to that of Cuvier, considers them as the 
respiratory organs. With respect to the intestinal canal and liver, nothing is added to the 
description given by Pallas. The branchie M. de Blainville supposes to have the power 
of projecting outwardly, though not to the same extent as the arms in Lingula, and thus 
to contribute to open the shell. Of the muscular apparatus of Terebratula he conjectures 
part to belong to the visceral mass, and was unable to distinguish more than two pairs 
belonging to the valves. The extremities of both these pairs he describes as attached to 
the valves, but considers it very probable that some of the fibres may pass through the 
orifice of the perforated valve, or be attached to the membrane which closes that orifice. 
From the particulars he was enabled to ascertain concerning the organization of Tere- 
bratula, and with the conviction that the branchie@ are not attached to the mantle, he 
considers that genus as intermediate to the true Palliobranchiata (Lingula, e. g.,) and 
the Lamellibranchiate Bialves. 
In the latest edition of the ‘Réegne Animal’ Cuvier retains his original opinion 
respecting the nature of the fringed or pinnate labial processes of Terebratula, still 
calling them arms: his description, however, of the muscles of the valves is liable to 
the same objection as those of the preceding authors, since, with the exception of 
one pair, they do not go from one valve to the other. He describes the ovaries as 
ramified productions adherent to each valve, but is doubtful as to the position of the 
branche. 
On account of the peculiar interest attached to this genus, both from its anatomical! 
and geological relations, and from the contrariety of opinions entertained respecting 
some of its most important organs, I felt considerable pleasure at receiving from 
Mr. Cuming a small, recent, and well preserved specimen of Ter. Chilensis, Brod. ; 
and I am much gratified in having this opportunity of acknowledging the liberality with 
which he has submitted to me the numerous specimens of the animals of rare and in- 
teresting species of shells collected by him. 
From observations on the young specimen of Ter. Chilensis, I was at first inclined 
to suppose that the coagulated contents of the branchial veins might have been mis- 
taken for the ova ; but having subsequently received three full-grown specimens, con- 
taining two distinct species of Terebratula?, through the kindness of Capt. P. P. King, 
and having more recently dissected a well preserved Ter. psittacea, Brug., taken by 
1 Tom, li. p. 130. 2 Ter. dorsata, Brug., and Ter. Sowerbii, King, Zool. Journ., vol. v. p. 338. 
