Fishes of the JVe stern North Atlantic 525 



broad above axis as below, with longer or shorter terminal filament; its lower side (as 

 determined by presence of horny rays) extending rearward as a narrow band for a con- 

 siderable distance beyond termination of upper side. Eyes oval, their vertical diameter 

 about ^U—^li as great as height of head at level of center of eye. Lower lip adnate to jaw 

 centrally but forming a free fold on either side, continuous with outer subdivision of 

 upper lip. Free tongue close-set with papillae. Roof of mouth strewn sparsely with small 

 rounded knobs. Dental plates with thin outer and anterior margins forming a continuous 

 cutting edge; anterior upper pair quadrangular, strongly cupped anteroposteriorly, the 

 anterior part more or less distinctly sculptured with about 5-8 (perhaps more) low 

 rounded radial ridges; posterior upper pair subtriangular to rhomboid, posterior part 

 nearly flat transversely, with 1—4 low longitudinal ridges (tritors); lower plates rhom- 

 boid, the anterior margin more or less deeply excavate, the posterior part more or less 

 deeply biconcave transversely, with prominent median elevation (tritor). 



Claspers of male trifid in all members of the genus for which they are known ;^2 the 

 accessory third branch slender, rod-like and smooth-skinned, its tip more or less dilated, 

 diverging from inner main branch and lying in a groove along ventral side of latter; 

 each of the main branches much broader, fleshy, with rounded or truncate tip, the 

 dorsal and lateral surfaces rough with small sharp thorn-like denticles directed toward 

 base of clasper. Prepelvic tenacula with narrower anterior cartilage articulated to pelvis 

 and broader posterior cartilage flexibly joined along anterior edge to anterior cartilage. 



Egg Capsules.*^ Embryo case described as tadpole-shaped, with tapering rearward 

 extension continuing as a filament; lateral flanges narrow, interrupted (or nearly so) 

 abreast broadest part of embryo case, without transverse thickenings; both sides of 

 capsule smooth; dorsal and ventral keels reported for some capsules but not for all. 

 Opercular slits extending forward to anterior end of embryo case; their edges described 

 as having "protruding serrulae, interlocking to form a close-set grating;"** also a con- 

 siderable number of pores along edges of posterior extension of embryo case, some on 

 dorsal side, some on ventral.*^ The opening by which the young fish escapes breaks 

 across the anterior edge of the embryo case. No doubt the embryo lies with its right- 

 and left-hand sides next to the sides of the case that bear the lateral flanges, since this 

 is true of the closely related Hydrolagus colliei (p. 534). It is supposed that the egg 

 capsules either lie free on the sea floor or that their tapering posterior extensions are 

 partially implanted in the mud or sand. 



Range. Representatives of the genus Chimaera, as here limited, are definitely known 



42. The claspers of C. pseudomonstrosa Fang and Wang (Contr. biol. Lab. Sci. Soc. China, 8, 1932: 280) from China 

 have not been seen. 



43. The earliest account of egg capsules of Chimaera monstrosa actually found in the oviducts of the parent fish seems to 

 have been by Lilljeborg (Sverig. Norg. Fisk., 3, 1884-1891: 527); the earliest description, with illustration, of cap- 

 sules of proven identity was by Grieg (Bergens Mus. Aarb. [1894-1895], 5, 1896: 12-13). Fo"" more recent illustra- 

 tions of the capsules of C. monstrosa and of the Japanese C. phantasma, with comparison of the two species, see Dean 

 (J. Coll. Sci. Tokyo, 79 [3], 1904: 6, pi. i, fig. 4; Chimaeroid Fishes, Publ. Carneg. Instn., 32, 1906: 35, 39, figs. 17, 



44. Dean, Chimaeroid Fishes, Publ. Carneg. Instn., 32, 1906: 28. 



45. 75 pairs of these pores reported for C. monstrosa, 62 pairs for C. phantasma (Dean, Chimaeroid Fishes, Publ. Carneg. 

 Instn., 32, 1906: 30). 



