130 = S. W. Ford—Development of Olenellus asaphoides. 
appendages beyond the contour—in any other species of 
trilobite. 
The surface of the cheeks in the specimen under wipiig is 
beautifully ornamented with fine, waved, radiating lines as 
the adult. 
I may also add, that several of the different stages of growth 
observed are shown to be represented by two distinct forms, 
respectively a long and a broad form. The same thing has 
been stated by Barrande for a large number of Bohemian 
species. Some of the ~~ forms were very diminutive, the 
smallest specimen now in my possession being one-third smaller 
than the smallest axiniple yet illustrated. I have also observed 
oe specimen the width of which did not exceed ;',th of an 
neh 
. 
eee York, December 10th, 1877. 
* Neither the small trilobite scorers ph a a by G. Linnarsson under the n 
of Paradoxides aculeatus isha ransaction e Geol. Soc. of Stockholm for 1877, | ‘ 
aaa nor the Hage previously de ribo s as Paradoxides Kjerulfi by J. G. O. Lin- 
on furnish, in ilobi 
n roof of 
oumgeat in their structure, a generic identity with Olenellus asaphoides. Moreover, 
I greatly question ‘whether the two Swedish species above mentioned are truly 
—_——_ i 0 i oly 
mn 
There is nothing, to my mind, in the structure of the specimens figured. to ead to a 
comparison of the posterior spines of P_aculeatus wtth the smaller pair of P. Kjerulji. 
In regard to Mr. Linnarsson’s somewhat extended, but, as it appears to me, too 
sa 
reason to change any o of the statements Seer in my former paper. hatever 
L son’s P% le ove to be, I fid spiaiert 
that Olenellus a is et a true Par Wheat the development of some 
species of Paradoxides shall have been any on (if, indeed, any of the species ever 
sustained gee we shall probably , able to satisfy ourselve os more fully upon 
this point. The smaller spines of the posterior margin of P. mag — : 
a ece n with the in cathe tects cakes and G. Li 
was the first to perceive this; but at present I think it axeeey doubtful wbeaiae 
they can be properly regarded as homologous. ‘This will become the ache ge 
¢ i is 
4 and 
it may, the relations of the two genera are manifestly very close, and the Sw 
beds fortunately promise to contribute and toward working them out to com- 
leteness. Mr. Linnarsson considers peg ar and 
. aculeatus, one example of which he owe figures, an picheginka form of t 7 same 
— but finding that the forms of my young not his 
e thinks my account most probably deeply in fault. Were his conclusions 
and ame, 8 portray: yep by a better array of facts drawn from his own speci 
field of observation they pen possess greater fitness and value. 
