CLARK: NEW FOSSILS FROM NEAR BOSTON. 479 
gins. No eye-lines are present. The eyes are situated on conical 
elevations of remarkable height, standing nearly twice as high 
as the glabella above the dorsal furrow. Each fixed cheek bears 
a very small tubercle near its posterior margin. 
It might be supposed that this specimen is immature, and 
merely represents the nepionic stage of some larger form. There 
are several reasons for disbelieving this. As far as we now know, 
the eyes and free cheeks are ventral on the protaspis, and if they 
are present at all in the adult, they travel during development 
over the margin and backward on the cephalon. Hence the larger 
the free cheeks and the farther back the ej-es occur, the later the 
stage in development. It would appear then that this specimen 
is at least in the neanic stage although it may not be as large as a 
full-grown individual. The presence of the highly elevated 
palpebral lobes indicates a stage of development beyond any 
nepionic stage known. The fact, too, that the glabellar furrows 
are mostly obliterated shows that the species is in an advanced 
stage of evolution as far as a Lower Cambrian form is concerned. 
One very remarkable feature about this trilobite is the presence 
of an anterior trans-glabcllar furrow. Obliteration of the furrows 
usually proceeds toward the posterior end, and seldom does the 
occipital furrow become obliterated. In our specimen there is no 
trace of the occipital furrow, but the anterior furrow has been 
retained, probably in the same way that the anterior furrow is 
kept in many Agnostids, as a retained larval characteristic. 
Bibliography of Lower akd Middle Cambrian 
Palaeontology of Eastern Massachusetts. 
Lower Cambrian. 
(Grabau, 189S and 1900, gives the bibliography to 1900.) 
Foerste, A. F. 
1899. [Geology of the Narragansctt Basin.] ]Monogr. V. S. Gcol. Surv., 
no. 33, p. 386-393. 
Grabau, A. W. 
1898. Guide to localities illustrating the geology, etc., of the vicinity of 
Boston. A. A. A. S., 50th Anniv. Meeting. Svo, Boston, 1S9S, p. 37-62. 
1900. Palaeontology of the Cambrian terranes of the Boston Basin. Occ, 
Papers Boston Soc. Nat. Hist., vol. 4, p. 601-GO-t, ])!. 31-39. 
