1198 



SCAX1>INA\IAN I'IMIKS. 



the iiterygoid cartilage passes into a narrow cartilage 

 whicli has heeu naiiierl tin' mainJihidoIiiioid, and on the 

 inner side of the last-mentioned cai-tilage, close to and 

 below the outside of the auditor)- capsule, lies a small, 

 narrow, oral hole {fenestra mandihido-hyoidea, ij). The 

 small part (Pakkeh's "ppdlrlr') in front of this hole 

 answers to the upjK'r end of the suspensorium: and 

 tlie l)art {]ii/(im(tndihidarc) that hounds the liole hchind 



Fig. 356. Cartilaginous framework of Uio tongue in Mi/.rine gliiti- 



iiosa, with the teetli in position, seen from above, X 5. 



After Parker. 



a, i, basihyal cartilages; c, supralingual cartilage; d, supralingual 



teetli; e, basibranchial cartilage. 



to the head of the hyoid arch. On the outside of the 

 anterior lateral fenestra there lie, behind the pterygoi- 

 deum a bi-oad plate of hard cartilage, answering to the 

 quadrate region {quadrattim, r), and behind this again 

 a soft cartilage {regio symplectica, s), which forms the 



posterior limit of the anterior later;il teiiestra and passes 

 inwards, behind the hard mandibiilo-liyoideum, into 

 another S(jft cartilage (hifcrhi/oideinii. f) and its conti- 

 nuation {epihyoideuni, ii). I'liese last-mentioned carti- 

 lages enut in an outward direction two soft cartilagi- 

 nous arches, tlie anterior (whose up])er ])art is named 

 the reratdlii/oideiivi (r), the extero-inferior ])art the 

 hypdhyoideum) bending outwards and downwards and 

 attaching itself to a hard cartilage (bitsiliyoideum), the 

 posterior {ejnhranchicde 'prmiini, x) curving downwards 

 and forwards and attaching itself annularly to the sj-m- 

 plectic region, together witli whicli it siu'i'ounds a large 

 hole {fenestra Jateralh jjasterior, //). On the inside of, 

 but not directly continuous witii, the interhyoideuin, 

 epihyoideuni, and sjmplectic region, lies a cartilage 

 whicli answers to the first pharyngobranchial bone {£), 

 and which with its hard, clavate, anterior end, close 

 to the inner margin of the quadratum, occupies the 

 posterior part of the anterior lateral cavity and with 

 its soft, tapering, posterior end reaches a little way 

 behind the ejubranchial cartilage. The second branchial 

 arch {jiharyuyo-hranrJiiale secundum, a) is represented 

 onl}- by its })haryngeal, upj)er part, which is here com- 

 posed of a few medially corniected, .singularly' formed, 

 branched rods of soft cartilage, embedded in that fold 

 of the palatine mucous membrane which lies behind 

 tlie pharyngeal aperture of the nasal duct. 



The lingual apparatus of Myxinv displays an espe- 

 cially powerful development and is furnished with large 

 cartilages both hard and soft (fig. 85t>). Thus there 

 are four hard hasiliyal cartilayes {a, h) and on their 

 upper surface a part consisting of several cartilages 

 (the snpralhiyiial cartilages, c), -which bear tlie jiower- 

 fuUy developed siipralinyital teeth {d). Backwards from 

 the basihyal cartilage rims a dorsally grooved rod of 

 tibrocartilage (the hasihranchial caftUaye, e), which ex- 

 tends back to the region of the gill-sacs. 



The muscular system of Myxine exhil)its about 

 the same develoimiental type as that of Fetromyzon 

 and even, in the main, as that of the other piscine 

 orders, i. e. on each side a "yreat lateral muscle" di- 

 vided into very numerous parts {myomeres) by septa 

 of connective tissue {myocommata), and thus showing a 

 segmental arrangement, though the axial skeleton is 

 not segmented, and two ventral muscles. There being 

 no extremities, or lateral fins, the muscles belonging 

 to them are also \vanting; but the head, on the other 

 hand, contains rather numerous singular muscles, which' 



