Dr. W. B. Carpenter on Spirifer cuspidatus. 295. 
attenuated tentacles are seen protruding from the mouth of one. 
Enlarged under a lens. 
ig. 2. Tentacle of Leucodore, magnified. The organ is in the somewhat 
contracted condition in which it usually appears when the ani- 
mal is placed between glasses: a, ciliated groove on the inner 
surface ; b, cavity of tentacle; ce, blood-vessel. 
Fig. 5. Ciliated parasite attached to a fragment of the tentacle, a. x 700 
diams. 
PLATE XX. 
Fig. 1. Dodecaceria concharum, CErst., from a tangle-root, St. Andrews. 
Enlarged under a lens. 
Fig. 2. Hook of the same species. x 350 diams. 
Fig. 3. Extremities of two of the latter: a, of the same specimen; 8, of 
a developing or somewhat imperfect specimen. x 700 diams. 
Fig. 4. Bristles from a dried specimen in limestone from Torquay, sent 
by Dr. Bowerbank. Xx 350 diams. 
Fig. 5. Posterior hook of a small Sabella saxicava, from a dried specimen 
in a Balanus sent by Dr. Bowerbank. x 700 diams. 
Fig. 6. Thoracic hook of 8. savicava. X 350 diams. 
Fig. 7. Minute spear-shaped bristles accompanying the latter. x 700 
diams. 
Fig. 8. Bristles of the same species: a & b, two of the forms met with in 
the thoracic region, the latter being viewed laterally ; c, posterior 
bristle from the dried specimen referred to under fig.5. x 350 
diams. 
XXXIV.—On the Structure of the Shells of Brachiopoda. 
To the Editors of the Annals and Magazine of Natural History. 
_ Oban, Sept. 21, 1868. 
GENTLEMEN, 
On my return from the mission of scientific research into 
the zoology of the deep sea, with the charge of which I have 
had the honour to be entrusted by the Admiralty, at the in- 
stance of the Council of the Royal Society (and the very re- 
markable results of which will be made public at the earliest 
possible period), I find the note of Prof. King contaimed in your 
last Number, on which I have only to remark that the admis- 
sion he has cited of the fallacy of his original imputation upon 
the accuracy of my researches into the structure of the shells 
of Brachiopoda is limited to the single case of the recent 
Rhynchonella psittacea, which did not enter into his original 
charge, because he had not then examined it. That charge 
was founded upon his superficial examination of fossil Rhyn- 
chonellida and Spirtferida; and neither then nor since has 
Prof. King made the slightest retractation of it. By declining 
to reply to my last three questions, he leaves the matter ex- 
actly where it was before; so that it must be presumed that 
