330 Proceedings of Royal Society of Edinburgh. [mat 7, 
considers hydroceplialus to be tbe cause of the condition, and to 
have acted before the fourth month. 
XII. Onufrowicz, Arch. f. Psychiatrie, xviii., 1887, p. 306, 
figs. 16, 17, 18, 19, 20. — Male, aged 35. Died of pneumonia; 
extremely idiotic. (The very full description in the original article 
should be read.) Brain very small ; convolutions on median surface 
show the apparent absence of the gyrus fornicatus (fig. 16, gf.)\ 
the calloso-marginal fissure (c.m.) present only in its posterior part; 
parieto-occipital {p.o.) and calcarine (c) fissures do not meet ; gyrus 
hippocampi {h) and gyrus uncinatus {u) well developed. (There 
are other abnormalities not of special interest here.) Corpus 
callosum absent; in its place a thin membrane {l.t.), which must he 
considered as the representative of the lamina terminalis (the tela 
choroidea superior). Psalterium of fornix absent; fornix (/) and 
septum lucidum {spt) displaced laterally. Anterior commissure (a.e.) 
present; middle absent; posterior cornu of latter ventricle {l.v.) 
dilated. On transverse sections a structure (see figs. 17, 18, 19, 20, 
(aof) similar to that marked spt and srb in my case, and lying 
between grey matter and fornix, and considered to pass backwards 
into tapetum (^, fig. 20). Onufrowicz considers this strand the 
fronto-occipital association bundle, rendered prominent owing to the 
absence of the corpus callosum. 
XIII. Kaufmann, Arch. f. Psych., xviii. and xix. p. 769, figs. 21, 
22, 23, 24, 25. — Female, 24. After an accident at four years of age, her 
mental development was retarded and her general health impaired. 
When in hospital she showed feeble mental capacity, without any 
very marked psychical change. Died of chronic parenchymatous 
nephritis. Skull symmetrical ; dura mater normal ; pia mater 
oedematous, and slightly thickened. Two frontal lobes with included 
dura and pia united together. Corpus callosum absent ; in its place 
a thin fold of pia mater continuous in front with that lying between 
the two frontal lobes. Commissura media absent; commissura 
anterior and fornix (/) present ; choroid plexus and lateral ventricle 
present. The fornix runs along the inferior margin of a strand of 
white fibres {aof), running mostly in an antero-posterior direction. 
This is considered as the association system of frontal and occipital 
lobes, the superior longitudinal fasciculus of Burdach, which has 
become prominent owing to the absence of the corpus callosum (the 
