30 
William Patten. 
laspis and Tremataspis is indicated by the resemblance in their median orbits, lateral and 
post-orbital openings. 
The Asterolepidae and Tremataspidae are bound together more closely than before, 
owing to their possession of oar-like appendages, large centrally placed orbits, and to the 
arrangement of latéral line organs and oral plates. 
M. The Syncephalata : For the great phylum of the animal kingdom formed by the 
nnion of the Yertebrates and the Arthropods, I propose the name Syncephalata. 
The delimination of the Syncephalata can be only roughly determined, especially at 
the lower end of the phyllum. The main stalk consists of the Arachnids (including the Tri- 
lobites, Merostomata, and Limulus, which were probably derived from Phyllopod-like Cru- 
staceans); the Peltocephalata, and the Vertebrata. The point of divergence from the main 
stalk of such groups as the Insects, Crustacea, and the simplified and aberrant forms like 
the Ascidians, Amphioxus, Balenoglossus and otliers, are of minor importance and do not 
concern us liere. 
The justification of the term, Syncephalata , lies in the fact that in tliis vast sériés of 
segmented animais the concentration and specialization of the anterior body segments into 
a liead région is definit ely begun and completed. 
It is only when tliis group is viewed as a whole that we see these momentous struct¬ 
ural advances in their true perspective, and eau follow the endlessly varied theme that 
leads steadily and consistently onward toward the completion of the raost complex organic 
structure that lias ever been produced, the vertebrate head. 
