35 S Bashford Deari hiemorial Volume 



Neither Garman . 1SS5.2 nor Goodey 191l'M round anv ;r:racular cartilages in the 

 specimens dissected by them, and Fiirbrmger 19'- 3. p. 3S9 :cu::_ cr.'.y a single spiracular 

 cartilage in his specimen. Allis (1923, Fig. 22, pi. XIj found three small nodules of 

 cartilage situated in a loose prespiracular band of connective tissue 'which does not have 

 the same relations as a spiracular Kgament) on each side of one specimen. The cartilages 

 are described by Allis (,1923, p. 169) as follows: 



These cartilage present stnkjngly the appearance of being rudiments c^ tlie basal 

 portions of three adjoining branchial rays related to the mandibular arch, and, like the sir^le 

 spiracular cartilage described by Fiirbringer in the oae specimen esamined by him, they lie 

 lateral, and hence morphologically anterior, to the artery of die arch. They lie posterovoiGal 

 to that part of the spiracular canal that bears the pseudobranchial filaments and in no sup- 

 porting relations whatever to them, and hence, while possibly representing persistii^ 

 rudiments of mandihnlar rays, they may not be true spiracular cartilages, for Gegenbsur 

 (l872, p. 198) says that in aU the Plagiostomi in which it is found, die spir^orar csrrllige 

 always Hes in the anterior wall of the spiracular canal, and that, where there is a pseu i : r r:. r ;h, 

 the filaments of that organ lie direcdy upon die cartil^e. 



Evidently Daniel (1934, p. 63) considers that the dor^l s^ment of the second visceral 

 arch of Chlamydoselachus is not a true hyomandibular, since he vsmtes of it that "the 

 dorsal segment is on its way to become a hyomandibula or suspeosorium." According to 



Allis 1 1923 ,, there is no Hgament connecting the hyomandibular with the palatoquadrate; 

 there are, however, ligaments connecting the hyomandibular with the ~ ar. iirle \ leckePs 

 cartilage) in the region of the quadrato-mandibular articulation, and a broad capsular 

 ligament binding the hyomandibular strongly to the cranium. The slidir.g ar::cc-?-tion 

 of the hyomandibular with the cranium has already been described. The homolcgies of 

 the hyomandibular of fishes are discussed by Allis 1915 ar.d by Gregory 1933, pp. 

 80-82). Woodward (1921, p. 39) regards the hyoitybc s^ospension of the jaws, found in 

 nearly all modem sharks and skates, as a condiricr. secondarily itc?.:r.ed. while the primi' 

 tive mode of suspension oi the jaws is a]r.rh:;:vl:c. as ir. C'.s:.:S':.s:':i ir.z ir. the noti- 

 danids). One may well be puzzled to decide '.vhe:her the recud^r ~ode c: s'jsper.sion of 

 the jaw^s of Chlamydoselachus is azirhisrydc or hyostylic. It does not conform fully to 

 either type, but comes nearer to being hyostylic. Goodey '1910.1, p. 544 states un- 

 reservedly that "the suspension of the javrs is hyostylic."" 



The hyomandibular of Chlamydoselachus bears nine Garman, 1SS5.2 or more 

 cartilaginous branchial rays. Goodey (1910.1'; shows, in his Fig. 1, pi. XLIII, ten rrinchial 

 rays attached to the hyomandibular and one branchial ray sKghtly detached riom it. 

 Allis (1923), in his figure renroduced as my Figure 5, plate 11, shows nine branchial ravs 

 attached to the hyomandibular and live or sis others more or less detached bu: evidently 

 related to it. 



The ceratohyoids (Test-figure 24, c-hy) parallel the mandibular or Meckelmn carti' 

 lages {mX) and are intermediate in size between these and the ceratobranchials (c-br). 

 Viewed from below, as in Garman"s figure, the -^-isceral skeleton or Chlamydoselachus 



