THE SKELETON 23 



trabecular to which is fused the planum internasale (c.pl.in.) — a flat 

 cartilaginous plate connecting the nasal capsules ventrally. 



(ii) On the dorsal side of the nasal capsule is the fenestra dorsalis 

 nasi (fen.d.nas.) lying opposite to the fen. basalis. The nasal, pre- 

 frontal and frontal all assist in covering it. It is approximately quad- 

 rangular in shape and is bounded mesially by the columella ethmoi- 

 dalis (c.col.eth.) (Higgins), or the dorsal arch of the trabecula, while 

 postero-laterally it is bounded by tht planum conchale (c. pi. con.), and 

 antero-laterally by the cart, obliqua (c.obl.). 



(iii) Two fenestrae perforate the lateral wall of the nasal capsule. 

 The anterior and larger is xh.^ fenestra narina (fen.nar.) which sur- 

 rounds the external narial opening and its associated muscles. It is 

 bordered dorsally by the cart, obliqua^ posteriorly by the cart, retro- 

 narina (c.rt.nar.), and anteriorly by the cart, cupullaris (c.cup.). 



(iv) Posterior to the fenestra narina and separated from it by the 

 cart, retro-narina lies tht fenestra infra-conchalis (fen.i.ch.) (or lateralis, 

 Bruner). This opening lies at the extreme postero-lateral angle of 

 the nasal capsule and is considerably smaller than the others already 

 described. 



(v) The fenestra olfactoria (fen.ol.) penetrates the nasal capsule 

 from the cranial cavity and serves for the passage of the olfactory 

 nerves. 



The cartilago antorbitalis (c.a.or.) which separates the nasal capsule 

 from the orbit is perforated by a pair of foramina, the for. orbito- 

 nasale laterale (fo.o-nas.l.) and mediale (fo.o-nas.m.), through which 

 pass the terminal rami of N. ophthalmicus profundus V. 



Thus the primary olfactory capsules of the adult Salamander con- 

 sist of a series of cartilaginous bridges, while the intervening spaces 

 are roofed over by the investing bones of the secondary skeleton. In 

 addition to the cartilages already named in connexion with the 

 fenestrae there are the following small projections. From the 

 cart, ectochoanalis is a small backwardly projecting process which 

 Seydel calls the Gaumenfortsatz (pr.S.). From the anterior end of 

 each nasal capsule a small cartilaginous horn protrudes antero- 

 mesially. This is the processus prenasalis inferior lateralis (pr.nas.) and 

 represents the remains of the cornu trabecular Just below this pro- 

 cess is a small opening for the exit of a nerve. It is thcforamen apicale, 

 and, according to Bremer, it is not entirely constant. 



The olfactory capsules of either side are connected together ven- 

 trally by a flat plate of cartilage which projects backwards under the 

 anterior end of the brain, and extends forwards to about the centre 

 of the ethmoidal region. It is the planum internasale (c.pl.in.). The 



