iiA(;-Fisiii;s. 



1197 



In tlir lii-iul of Miixlne tlie (•;irtila,i;iiioiis skeleton 

 is e()ni]i!ii'ati\(4y Car more developed and complex. Here 

 we meet with two kinds of eartilaginous tissue, one 

 rather liard, of a yellowish colour, the other soft, colour- 

 less. This cartilage forms the floor of the cranium, as 

 well as a nund)er of pnjcesses and ai'ches uriginatiiig 

 therefrom and composing a singular framework or 

 "basket-work" within the head. No segmentation into 



fore end of the anterior iiitertrahecula and the anterior 

 opening of the nasal duct are two paii's of shoi't, some- 

 what curved, anteri<jrly jjointed rods of cartilage (m), 

 which are the supports of four — two on each side of 

 the nasal apertiu'c — tentacles or pa])ilhe ("barbels"). On 

 the outer side ('a(;h of the two trabecula' is bounded by 

 an elongate oval hole (fenestra .suhorbitalis, n) and on the 

 outside of the latter is another cartilage {pferyf/okleum. 



vertebral parts can be observed, as we have already j o), which here forms the outer edge of the cartilaginous 



stated; but by means of a comiiarison with I'ctriimiizoii 

 and its larval form and, above all, with the ]>li(Miomena 

 during the development of amphibian lai-\;c, it has 

 been attempted, not without success, to interpret in 

 detail the cartilaginous framework of the skull in 

 Mijx'Dte. Follow ing Pakkek's explanation we here give 

 a brief description (fig. 3.d5). 



The anterior conical termination of the notochord 

 is surrounded l)y a sheath of hard cartilage (the pafd- 

 chordal cdiiihif/e or investinfi mass, fig. 355, >>), which 

 in the median line exhibits a dorsal fissure and on 

 the sides passes into the rounded kidney-shaped audi- 

 tor!) capsules (c), also formed of hard cartilage, which 

 have their longitudinal axes directed from within and 

 behind outwards and forwards, and pi'esent on their 

 inner sujjerior side the foramina for the branches of 

 the auditory nerve. In frcint the parachordal cartilage 

 passes into two slender cartilaginous rods, the so-called 

 cranial fraheeulce (d), which enclose an elongate oval 

 hole (the hasicranial fontaneUe, e) composing the floor 

 of the cerebral cavity and in great part tilled by fibrous 

 connective tissue, but containing behind and in the 

 middle a spoon-shaped cartilage (the posterior i)itertr(i- 

 becula, /). Anteriorly the trabecula? pass on each side 

 into the palatine cartilages ((/), which, together with 

 the ethmoid cartilage (h) joining them to each other 

 in front, form the anterior limit of the fontanelle. Fi'om 

 tlic antci'ior ends of the jialatinc cartilages projects on 

 lach side a cartilaginous rod {coniu prfepalatinum, i), 

 curved outwards and forwards and ])ointed at the tip. 

 True cortma traljecularum are wanting. In the median 

 line lies a long cartilaginous rod (the anterior inter- 

 tndtecnla, k) originating from the dorsal side of the 

 interior termination of the fontanelle and from the 

 <thmoid region. This rod supports the long tube, 

 formed of transversa] cartilaginous rings, that com- 

 Idses the nasal dart (I) and leads behind partly to the 

 olfat-tory organ, ])artly to the palate, into the cavity 

 of which it has a free opening. On each side of the 



framework of the skull and behind borders on another, 

 larger hole (fenestra lateralis anterior, }>), also of an 

 elongate oval shape. On the inner side of this fenestra 



Fig. 355. Skull ni .\fi/xine glutino.ta, Sfcn from below, X 5. 

 After Parkkr. 

 (I, notochord; b, paracliorilal cartilage; (,', auditory capsules; d, trabe- 

 cule; e, basicranial fontanelle; /, posterior intertrabecula; y, palatine 

 cartilage ; /;, otlinioid cartilage ; /)/, etiinioidal tooth ; /, comua pra;- 

 palatina; k, anterior intertrabecula; I, nasal duct (in outline); m, carti- 

 laginous rods of the four circuninasal tentacles; n, suborbital fenestra; 

 0, ptcrygoideum ; /), anterior lateral fenestra; <], mandibnlo-hyoid 

 fenestra ; r, quadratuin ; s, symplcctic region ; t, interhyoideum ; u, epi- 

 liyoidenm; v, ceratoliyoideum, x, first epibrancliial; y, posterior lateral 

 fenestra; !, first pharyngobranchial; <2, second pharyngobranchial. 



