garman: the chimaeroids. 257 



species and genera. Three of the known Hving species are reported from the 

 soutliwestern coasts of South America; tlie other two are from Tasmania and 

 the Cape of Good Hope respectively. Tlie younger stages of all are similar. 

 Callorhynchus callorhynchus, Plate 7, Figures 7 to 9, is the species most widely 

 known ; in it the tritor of each palatine tooth occupies the greater part of the 

 entire length of the dental plate and sends forward two prongs, the inner of 

 the two being the longer. C. smythii, Plate 6, Figures 1 to 4, as already men- 

 tioned, has two distinct parallel tritors on each of the palatine teeth. Both of 

 these forms occur at Valparaiso and Talcahuano. C. tritoris is a new species 

 from the INIejillones ; one of its palatines and the vomerines are drawn on 

 Plate 6, Figure 9, where the tritor of the first is seen to be placed far back 

 on the tooth, to be broader than long and hardly notched anteriorly. In 

 C. milii, Plate 6, Figures 7 and 8, the prongs are short ; and the tritors have 

 a considerable forward extension on the palatine teeth, while the mandibular 

 tritor is short, rounded, or oblong, and like those of the palatines situated near 

 the posterior edge of the tooth. This is the Tasmanian species first named, 

 described, and figured by Bory, 1823, and later described by Richardson, 1841, 

 under the name C. tasmanius. Callorhynchus capensis, Plate 6, Figures 5 and 

 6, is marked by very slender and sharp forward extensions of the tritors on 

 both palatine and mandibular teeth ; these prongs are elongate and tapering, 

 and the hinder portion of the tritor on the palatine is comparatively short, but 

 on the mandibular teeth the posterior swollen portion of the tritor appears to 

 be longer than that of the tooth above it. This species was described by 

 Dume'ril, 1865, from specimens secured at the Cape of Good Hope; the figures 

 cited above were drawn from an individual sent by E. L. Layard, Esq., from 

 the same locality. Interest in C. capensis is heightened by the fact that traces 

 of its existence have been found in Cretaceous formations and in a locality 

 which greatly widens its distribution. For the species described by Xewton, 

 1876, in the Quarterly Journal of the Geological Society, p. 326, Vol. 3, and 

 figured and described by the same author, 1878, in the Memoirs of the Geologi- 

 cal Survey of the United Kingdom, IV., p. 41, Plate XII., Figures 11 and 12, 

 under the name Callorhynchus hectori, from a fossil palatine tooth found at 

 Amuri Bluff, New Zealand, in a fine conglomerate, believed to be of the age of 

 the Lower Greensand, of the Cretaceous, is not to be separated from C. capen- 

 sis by any of the characters at present known. This is the earliest positive 

 evidence of the existence of a species of now living Chimaeroid. 



The teeth of Chimaerae are more differentiated than those of any other 

 genus of the group. Judging from the dentition, the evolution of Chimaera, 

 as in the reduction of the rostrum, would appear to have gone a stage farther 

 than that of the species of Callorhynchus, and in doing this to have acquired 

 the peculiar laminated structure and the palatine and mandil)ular tritors on the 

 forward edges of the teeth. The ridges on the inner sides of these teeth may 

 be looked upon as remains of tritors, similar to those of Callorhynchus smythii, 

 Plate 6, Figures 1 and 2. If the rise of Chimaera were to be traced, there 

 would probably be found among its ancestors some with teeth like those of the 



