Systematic Position of the Trilohites. — Kintjsley. 33 
on the coast of New England as far south as cape Ann, and 
after the accumulation of the drumlins carrying a temperate 
fauna. These epochs may be correlated also with the diverse 
successive faunas of Sankaty head in Nantucket. 
THE SYSTEMATIC POSITION OF 
THE TRILOBITES. 
By J. S. KiNGSLEY, Tufts College ; 
With Remarks by C. E. Beecher. 
Within the past three or four years our knowledge of the 
structure of the trilohites has been wonderfully increased, un- 
til now it would seem that we must have a pretty accurate and 
detailed acquaintance with the external anatomy of one or 
two forms. I have had no opportunity for studying any of 
these recent finds and must rely upon the published accounts 
of the researches of others for my knowledge of details. My 
only excuse for entering upon this field is that I have some 
acquaintance with the structure of recent arthropods and 
that the conclusions to which I am led are somewhat at vari- 
ance with those which have been recently set forth. 
That the trilohites are true crustaceans seems now placed 
beyond a doubt; but their position within the crustacean 
phylum is by no means as certain. Of the recent authors who 
have discussed this matter, Bernard ('95) claims that the 
trilohites are closely related to the Xiphosures, and again in 
the same paper, that they "are, in reality, pre-crustacean. 
They represent a stage more primitive than Apus, /. e. nearer 
to the original annelidan ancestor of the whole phylum." 
Beecher, on the other hand ('95, '97), believes that thelarvte 
of the trilohites are closely related to the regular crustacean 
nauplius, and more nearly represent the primitive ancestral 
larval form of the crustacean than does the nauplius. Again 
('95) speaking of the adults he says that they "are shown to 
be a primitive type in (1) their multiple segmentation, (2) the 
irregular number of their thoracic appendages, and (3) the 
biramous structure of their legs. They therefore present 
clifeiracters common to the Entomostraca and Malacostraca." 
In reading Dr. Beecher's early papers one gets the impres- 
sion, although this is not definitel}' stated, that he is inclined 
