62 THOMAS HENRY HUXLEY 



the same order as that which contains the Quadrumana 

 [i.e., apes and monkeys]." 



A technical memoir, "On the Brain of Ateles 

 paniscus" (Proc. Zool. Soc, l86i, pp. 247-60. Sci. 

 Mem., ii, xxvii, p. 493), proves that certain structures 

 asserted to be peculiar to man are present in the brain of 

 this species of spider-monkey, a comparatively low type. 



The following important palseontological memoirs also 

 made their appearance in 1 861 : — 



1. " On Pteraspis Dunensis (Archseoteuthis Dunensis, 

 Roemer)" (Q. J. Geol. Soc, xvii. 1861, pp. 163-6. 

 Read January 23, 1861. Sci. Mem., ii, xxii, p. 417). 

 — The fossil described was shown to be the head-shield 

 of an ancient vertebrate, and not the pen of an extinct 

 cuttle-fish, as supposed by the first describer. The 

 affinity with sturgeons suggested has not been justified 

 by subsequent research, Pteraspis and its allies being 

 now regarded as constituting a group lower in the scale 

 than any known fishes. 



2. " Preliminary Essay upon the Systematic Arrange- 

 ment of the Fishes of the Devonian Epoch " (Mems. 

 Geol. Survey U.K., Decade X., 1 861. Sci. Mem., ii, 

 xxiii, p. 421). — In this important memoir the founda- 

 tions of a rational classification of extinct fishes, especially 

 those known as Ganoids (of which sturgeons are the 

 best-known living examples), are laid down. In the same 

 decade two memoirs on particular extinct types of fish 

 are included, i.e. : — 



3. " Glyptolaemus Kinnairdi" (op. cit., pp. 41-6. Sci. 

 Mem., ii, xxiv, p. 461); and 4. " Phaneropleuron 

 Andersoni" (op. cit., pp. 47-9. Sci. Mem., ii, xxv, 

 p. 467). 



Huxley had already made a special study of the verte- 

 brate skull (cf. p. 40), and in the course of this year con- 



