Raymond : Notes on Ordovician Trilohitrs. 73 



thDiight that they are the ymini; of Amphilichns minganensis, although 

 a typical example of that species has never been found with them. The 

 glabellar furrows of these specimens do not extend back to the neck-ring 

 as in Amphilichas minganensis, but die out a short distance in front of it. 

 At their posterior ends they turn slightly outward, ending in a sort of pit. 

 In one specimen there is another pit on each furrow about halfway between 

 the posterior end of the furrow and the frontal border. These pits are 

 probably the remnants of the inner portions of the second and third 

 pairs of glabellar furrows, and the development of the glabella seems to 

 have been similar to that of the Fjicriciiiiiridce and Acidiispidcc. Reed has 

 shown that in the section of the Lichadidce to which Aniphilichas belongs 

 the side lobes are the fused, second, third, and fourth glabellar lobes, and 

 that the glabellar furrows are the first pair prolonged by the uniting of 

 the inner ends of all three pairs of furrows. The anterior portion of a 

 glabellar furrow, back to the first pit shown on these small specimens, would 

 be interpreted as the original first glabellar furrow. As the animal grew, 

 the muscular attachment became localized in one point, the inner end of 

 each furrow. The shell being thin, the side lobes bulged, obliterating 

 most of the furrow, and a secondary furrow was produced, connecting the 

 inner ends of the original furrows with the anterior furrow. That the 

 glabellar furrows originated in this way is shown by the fact that in the 

 adult they are not straight, but there is a slight ofT-set marking the position 

 of each of the pits seen on these immature specimens. According to this 

 theory of the development of the glabella, the uniting of the ends of the 

 furrows proceeding from the front backward, the specimens here discussed 

 might represent a step either in the ontogeny or the phylogeny. As they 

 are all small, it is most probable that they are immature individuals. 



Reed has described as Amphilichas sp. a large cranidium from the 

 Llandeilo of Girvan which has glabellar furrows which die out before the 

 neck-furrow is reached,'' and the same character is seen in some specimens 

 of Amphilichas lineatus (Angelin).^ 



Family ACIDASPID^ Barrande. 



Genus Ceratocephala Warder. 



Ceratocephala narrawayi sp. nov. 



Plate XVIII, figure 5; Plate XIX, figure 15. 



In a fragment of limestone from the middle Chazy at Chazy, Xew York, 



was found a minute glabella of a species of Ceratocephala. This is of 



Taleonlographical Society, 1906, 109, pi. 15, figs. 4, 5. 



'Revision der Ostbaltischen Silurischen Trilobiten, II, 1885, pi. 6, fig. 5. 



