116 
ORIGINAL ARTICLES. 
favour Darwin’s opinion, who considers them to he organs of hear¬ 
ing.” 
My object in asking yon to publish this note, is to induce some 
one to attend to this curious organ ; to endeavour to discover ova 
within the so-called auditory sack ; for as each cirripede produces so 
many eggs, assuredly this might be effected without great difficulty. 
It is, however, possible (as I believe was suggested by Mr. R. Garner 
at the British Association, but whose paper I have mislaid,) that 
cirripedes, like certain Entomostraca, may lay two kinds of eggs ; one 
set passing out through the problematical orifices; and another set 
coming out of the body in sheets, in the manner suggested by me;— 
namely, the ova collecting under the lining membrane of the sack 
before the act of exuviation, with a new membrane formed beneath 
them ; so that the layer of eggs becomes external after the act of 
exuviation. If this view, to which I was led by many appearances, 
be correct, improbable as it may seem, it ought not to be difficult to 
find a specimen with the old membrane of the sack loose and ready 
to be moulted, with the new underlying membrane almost perfect, 
and with the layer of ova between them. Or a specimen might be 
found which had lately moulted, with its skin still soft, (and this I 
believe that I saw) with a layer of eggs still loosely attached to the 
new lining membrane of the sack. 
VIII.—On Ribs and Transverse Processes, with special re¬ 
lation to the Theory oe the Vertebrate Skeleton. By 
John Cleland, M.D., Demonstrator of Anatomy, University of 
Glasgow. 
(Read at the Meeting of the British Association at Cambridge, October, 1862 .) 
While it often happens that, on comparing structure with structure in 
series of animals, anatomists become aware of close correspondences 
between objects that to all outward appearance are very different, in 
the comparison of ribs or transverse processes in the various regions 
of one animal, or in the series of vertebrata, what strikes the eye at 
first is their resemblance. They are naturally, in the first instance, 
assumed to correspond, and only when differences of detail one by 
one attract attention, is that first assumption put upon its trial and, 
by different judges, to a greater or less extent, set aside. The amount 
of palpable resemblance between vertebrae gives an air of simplicity 
to the question of the correspondence of their parts, when compared 
with questions which present themselves in connexion with the skull; 
and while some inquiries as to correspondences of cranial bones are 
liable to be cast aside as little better than dreams, the legitimacy of 
inquiring what parts of vertebrae correspond one to another stands 
beyond all question. It is important, therefore, for the interests of 
