y^y^ 



/» BAL-liNIDiE. 



Yet I think it is so important that wo shoiild avail ourselves of 

 every assistance in determining the species of these animals which 

 are so difficidt to observe, that one must run the risk of making 

 such a mistake, as it can easily be corrected when the opportunity 

 occirrs to some competent naturalist to examine a specimen containing 

 both the baleen and the ear-bones. 



The tympanic bones are often found fossil. Professor Owen, in 

 the ' Hist. I5rit. Fossil Mammals,' has named and figured the ear- 

 bones of the genus BaUrna which have been observed in the Crag ; he 

 has named them as if he regarded the following as distinct species : — 

 1. Balcena aff,ms, tig. 221 ; 2. B. dejinita, fig. 222 ; 3. B. gibhosa, 

 fig. 223 ; 4. B. emanjhiafa, fig. 224. These bones are all very im- 

 perfect, and the figures of the two latter are not sufficient even to 

 decide whether they belong to the genus Balcpna or to Phi/sahts. 

 They differ in the recent genera, thus : — ■ 



Tympanic bone rhombic ; aperture oblong, only slightly contracted 

 at the upper end, and about two-thirds of the length of the 

 bone. BALiENA, EuBALiEXA, and HunteplItts. 

 Tympanic bone irregular rhombic ; apertirre irregular, much con- 

 tracted at the upper end, and the wide part not half the length 

 of the bone. Capeeea. 

 " Dans les galeries d'anatomie comparee du Museum de Paris parmi 

 les preparations des os d'oreille nous avons trouve dans un meme 

 cadre une caisse tjTapanique de Balcena Mysficetus, une autre de 

 Balcena ausf rails, une de Pterobalcena commums, et une de Ptero- 

 halcena glr/as." — Vcm Beneden, in Mem. Acad. So i/. de Bruxell es,lSGl, 

 xxxii. 38. 



Synopsis of the G-enera. 



I. Atlas united mth the other cervical vertebrce into one ma^s ; the lateral 

 process of the axis smcdl, broad, solid. 



A. Baleen thin, polished, tvith a thick enamel coat and ajinefriiir/e. 



1. Bal^na. First rib slender ii©«*5 and undivided at the vertebral end. 



Tympanic bone square ; apertine nearly as long as the bone. 



B. Baleen thick, not jiolished, with a thin enamel coat and a coarse thick 



fringe. 



2. Eubal-5:na. First rib broad at the vertebral end. T3anpanic bone 



square ; apertm'e nearly as long as the bone. 



3. HuNTEHirs. First rib broad, with a double head at the vertebral end. 



Tympanic bone square ; aperture nearly as long as the bone. 



4. Capeeea. First rib ? Baleen P Tympanic bone irregular 



rhombic ; aperture irregular, much contracted at the upper end, and 

 the wide part not half the length of the bone. 



n. Atlas free from the other cervical vertebra, which are muted into a 

 single mass ; the lateral process of the cur is rounded. 



5. Macleayius. The lateral process of the axis truncated. 



G. ? Paljeocetus. The lateral process of the axis produced, rounded, 

 slightly perforated. 



