Rte and Zoology. 133 
as is also ¢ pe as fly enunciated in his several 
articles on cephalization. M1 er was, moreover, so far misled as to 
have entirely mistaken oot real axial elation among Brachiopoda upon 
which his conclusions were based, as well shown y Mr. . Morse,* 
although a a rved hice still oberg and had been previously 
ve by ot 
iiterior and posterior, while others, as an and m 
anatomists and conchologists, regarded thes as fisteat adh rela the 
only question being as to which valve was dorsal and which ventral. 
Either of these three views would obviously allow the same lateral 
symmetry, a plane dividing the animal in equal, halves coinciding with 
both these axes. But if “ lateratity” be characteristic, and distinct from 
lateral symmetr y, in Mollusca, it should be more clearly defined than any 
one has yet been able to do. 
_ The indefinite nature of these terms, as employed by Agassiz, will 
c. Bost. Soc. Nat. Hist., ix, 57, see also Proceedings Essex Institute, iv, 162. 
ome remarks of Prof. Agassiz referred to are as follows: “ He thought bilate- 
I ro ity w 
y. dia’ 
and by cephality the preponderance of the head and its contained organs in t 
Vertebrates, ” If, therefore, Jaterality Ne 1 vee the arrangement of organs on the 
sides without reference to symmetry, it will be a sigourotis that er organs of Articu 
lates,the le egs, ja ns of senses, branchie, and t . spiracles and 
f In 
above a seotig these ani a as among Mollusca 
where the h presen — in respect to imentary canal, ai 
iam he is ve "hil in some, spat 20 of the themselves are 
dorsal and ven The position of fthe § iracles and trachee in Insects is also 
as to refute the idea of “ tergality” mipraie vbr they agree with that of later- 
ie i) Sati al we otter: IucOnaternpedie die 
rif we regarded merely the ordinary ee ” e 
“ites, and Cephalopods it is Lecsiaany less m than in Provcorerseng even in 
Lamellibranchiates the folds of the mantle, wit ith yo valves of shell that 
secrete 
and the branchial fo lds, which rest upon the sides of the body, originate dorsally and 
extend downward upon the sides, while the hinge and its a sphere noe B 
