ON THE GENERAL MORPHOLOGY OF THE MYXINOID FISHES. 



341 



(50) ScHREiNBR, K. E., 1898. Berijen's Mus. Aarb., No. L Review: Zool. Central, Bd. vii. p. 66, 1898. 



Histology of gut of Myxine. 



(51) Stannius, ] 854. Zootomie d. Fische, 2nd ed. Berlin. 



General anatomy of Myxinoids. 



(52) Stockard, 1906. Amer. Jour. Anat., vol. v. p. 481. 



Development of mouth and gills of Bdellostoma. 



(53) Stockard, 1906. Anat. Anz., Bd. xxix. p. 91. 



Development of Thyroid of Bdellostoma. 



(54) Stockard, 1908. Anat. Rec, vol. ii. p. 336. 



Gill position of Myxinoids. 



(55) WiEDERSHBiM, 1883. Lelir. d. vergleich. Anat., pp. 590 and 603. 



Gut and biliary apparatus of Myxine. 



(56) WoRTHiNGTON, 1905. Ainer. Nat., vol. xxxix. p. 625. 



Gills of Bdellostoma. 



L. EXPLANATION OF PLATES. 



Rbpbrbnce Letters. 



an. 



a.p.v. 

 a.s. 



b.d. 



anus 



two 



a.d.p. Anterior arch of the dental plate. 

 a.h.d. Anterior hepatic duct. 

 a.h.v. Anterior hepatic vein. 

 a.l.l. Anterior lobe of the liver. 

 an. Anus. 



Posterior extremity of roof of 

 partially dividing cloaca into 

 chambers. 

 Anterior portal vein. 

 "Aquseductus Sylvii," or forward 

 prolongation of the mesencephalic 

 ventricle. 

 Bile duct. 

 b.g. Biliary gland or "pancreas." 

 h.o. Bulbus olfactorius. 



b.p. Pad of soft pseudo-cartilage at the 

 anterior end of the anterior segment 

 of the basal plate. 

 b.p.^~^ Anterior, middle, and posterior segments 



of the basal plate. 

 br.a.^ "First branchial arch." 

 br.a."^ " Second branchial arch." 



7 // T^. •, f external branchial apertures. 

 or.ap. Right J 



br.cl. Branchial cloaca. 

 c.ao. Ventral or cardiac aorta. 

 c.b.c' Paired anterior limb of the M. con- 

 strictor branchiarum et cardise. 

 Second loop of the same muscle. 

 Third loop of the same muscle at the 



bend (cp. Part II., fig. 2). 

 Cornual cartilage. 



c.b.c. 



c.b.c." 



e.c. 



c.e. 

 e.e.' 

 c.e." 



c.g.p. 



c.g.p. 



c.g.p." 



c.g.s. 



c.g.s.' 



c.g.if." 



c.h. 



cl. 



coe.a. 

 cp.' 

 c.p." 



cp.'" 

 ep.c. 

 e.pl. 



cp.t.c. 



cp.t.c' 

 cp.t.c." 



c.p.v. 



c.q.p. 



c.q.s. 

 d.m. 



of the M. 

 moidalis. 



copulo - eth- 



TRANS. ROY. SOC. EDIN., VOL. XLIX. PART II. (NO. 3). 



External head ^ 

 Internal head 

 Fused external 



and internal 



heads 

 Tendon of the M. copulo-glossus 



profundus, the protractor muscle of 



the dental plate. 

 Lateral head ) of the M. copulo-glossus 

 Median head J profundus. 

 M. copulo-glossus superficialis. 

 Median slip of tendon of above to 



ventral skin. 

 Lateral slip of same tendon. 

 M. cranio-hyoideus. 

 Cloaca. 

 Coeliac artery. 



I M. constrictor pharyngis — first, second, 

 j and third divisions. 



M. copulo-copularis. 



M. copulo-palatinus. 



Principal head 



Posterior division 



Aiiterior division 



Common portal vein. 



M. copulo-quadratus profundus. 



M. copulo-quadratus superficialis. 



Area of mucosa immediately behind the 

 dental apparatus puckered by tne 

 withdrawal of the latter. It flattens 

 out when the teeth are protruded. 



44 



of the M. copulo-ten- 

 tac u lo-coroD arius. 



