316 



MISS 10. A. KIIAS15II ON 'I'll 10 DIOVELOl'MENT 



it passes back wards and downwai'ds as a solid band of mesen- 

 cliyme through wliich I'uns the naso-ciliary branch of the tri- 

 geminal just whore this branch joins tlie ophthalmic. This band 

 continues ventrally, anterior to the Gasserian ganglion, to join 

 the intermediai-e ma,ss, the latter being connected posteriorly by 

 a thin streani of cells round the antoi-o-venti'al side of the same 

 ganglion with the maxillo-niandibnlar muscle-mass. No iniion 

 witjj tlie nuixillo-mandibular mesenchyme can be traced in either 



Text-figure 1 2. 

 f^- h.c. 



op.c. 



Trivhomrus milpecula. G.L. 7*25 nun. (XII a. '02). 



Loii'iitudiiial section (S 10-3-1), passing about half-way through the riglit head- 

 oavity {r.li.c), to show the primovdiuui of the ni. obliquus inferior {o.inf.} and 

 tlie anterior portion (r.c.) of the abduceiis niuscle-niass lying behind the cavity 

 and ininiediately in front of the vena capitis niedialis (v.c.m.) and the vena 

 cerebralis anterior {r.c.a.}. The oculomotor (III.) runs down between the 

 cavitv and the aliducens mass. X llU. 



(T.c.a.^arteria cerebri anterior. o/).c. = optic cup. v.o.i. 

 inferior. 



vena orbitalis 



of the transverse series, but the intermediate mass in all three 

 embryos is still joined with the dorsal outer end of the anterior 

 portion of the abducens complex. In the transverse series (c) 

 the intermediate mass appears to have lost its connection with 

 the m. obliquus superior and is apparently degenerating. 



'VUo oculomotor nerve, descendinsr almost directiv ventrallv 



