lyo 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 52 



water itself would find exit as usual, relieved of a large part of its 

 life. 



Fig. 54. — A Branchial Arch with Annexed Organs; transverse section next to 

 the articulation of the arch (semischematic). 



0. Branchial arch with fossa of adductor muscle. 



b. One of the cartilaginous rays of the branchial diaphragm adherent to the 



anterior branchial lamellae. 



c. Accessory stem which connects with the arch. 



d. Muscle of the branchial diaphragm or interbranchial muscle to which 



posterior branchial lamellae adhere. 



e. Adductor muscle of the ceratobranchial and epibranchial parts of the arch. 

 ff. Branchial lamellae whose external surface as usual is folded. 



gg. Cartilaginous stems of the bases of the branchial lamellae. 



hh. Muscles which unite the latter to the arch. 



it. Hydrophorous canals. 



jj. Prebranchial appendages in profile. 



/. Branch of the branchial artery. 



mm. Branchial veins with efferent lamellar branches, from which proceed the 



branches for the prebranchial appendages. 

 n. Principal nervous trunk. 

 X. Fold of mucosa covering partly the branchial lamellae. 



VI 



The Devil-fishes, of course, like other Selachians, come together 

 in sexual intercourse.^ The details of their union as well as the 



'According to Risso (Hist. Nat. Europe Men, 1826, p. 165) the female of the 

 M. giorna is always (toujours) much larger than the males. No observations 

 have been made on the American Devil-fish ; it is to be hoped that some 

 may be. 



