CEREBRAL CONVOLUTIONS — " SALLY." 79 



frout of and nearly parallel to the upper part of the fissure of 

 Rolando is a conspicuous fissure which passes for some dis- 

 tance forwards^ nearly parallel with the median fissure^ for 

 about half the length of the lobe. This appears to repre- 

 sent a portion of the sulcus frontalis primus (/^.), together 

 with the uppermost part of the sulcus prsecentralis superior 

 ip.c.s.). 



At a point a short distance behind its anterior termination 

 a fissure passes downwards and slightly backwards, nearly 

 parallel with the fissure of Rolando, and before it ceases gives 

 rise to another fissure directed nearly horizontally forwards 

 (/i.). A triradiate fissure results; the lower, posteriorly di- 

 rected limb ends freely, the upper limb joins the sulcus fron- 

 talis primus. This triradiate fissure appears to represent the 

 '' ramus horizontalis " which is connected with the vertical 

 limb of the sulcus prsecentralis inferior {p. c. i.). 



The sulcus prsecentralis inferior {p. c. i.) passes downwards 

 and backwards in the usual way, and near its lower end is 

 apparently connected with a branch of the sulcus fronto- 

 orbitalis (e. o.), from which, however, it is separated by a deep- 

 lying concealed gyrus. 



Behind the praecentralis inferior lies a particularly long 

 sulcus diagonalis (d.) which reaches very nearly up to the 

 ramus horizontalis, and occupies a similar position and has 

 about the same extent as the same fissure in the oranges 

 brain figured by Cunningham, and reproduced here on fig. 46. 



The arrangement of these fissures is very similar to that 

 figured for a human foetus of the seventh month on p. 268, 

 fig. 60, of Dr. Cunningham' memoir. 



This system of fissure is no doubt very peculiar — unusual, 

 though not unknown ; connections take place in such a way 

 that we have a practically continuous series of furrows repre- 

 senting sulcus praecentralis superior, sulcus frontalis primus, 

 ramus horizontalis, and sulcus diagonalis. 



Between the upper end of this composite furrow and the 

 Rolandic fissure is a short, obliquely placed furrow (a.), which 

 appears to be the " sulcus praecentralis marginalis." The 



