456 MR. A. H. G. DORAN ON THE MORPHOLOGY 



like that of Megaptera, it exhibits intermediate characters between Balcena and Balceno- 

 ptera. It is larger than the malleus of an adult Balcena ; its head is less flattened than 

 in Balcenoptera. The upper facet of the articular surface is extremely wide and almost 

 plane ; the lower is small, and as convex as in most Cetaceans ; it must be remembered 

 that in the Greenland Whale and Southern Whale the former facet is rather larger than 

 in Balcenoptera. From the front of the head a process projects, which bears on its inner 

 side a sharp spine (mn), directed more downwards and less compressed against the body 

 of the malleus than in the last-mentioned whale, but neither so long nor directed so much 

 downwards as the stout curved manubrium of Balcena, which it represents (PL LXII. 

 fig. 28, PL LXIII. fig. 13, mn). 



In the plates illustrating Camper's ' Observations Anatomiques sur la Structure et le 

 Squelette des Cetac^s ' the ossicula of Physeter are very correctly figured. He speaks 

 of " la manche, ou l'apophyse de K-au " as if those terms were synonymous ; the site of 

 the insertion of the tensor tympani is not mentioned or indicated. 



The malleus in the Cachalot and in the Ziphioid Whales possesses highly distinctive 

 characters. 



This ossicle in Physeter macrocephalus (PL LXII. fig. 34) is very small in proportion 

 to the bulk of the animal. In general form it may be compared to a half-split pea, 

 which it hardly exceeds in size. The head is small and convex ; it does not bulge or rise 

 high over the upper facet. The depression on its outer aspect exists, but is not so 

 extensive as in any of the Balsenoidea. The articular surface is very wide, considering 

 the ill-development of most of the elements of the bone. Its upper facet is very broad 

 and almost plane, the lower is much smaller, convex, and everted, like the mouth of a 

 pitcher. 



The process connecting the malleus to the tympanic bone is extremely short, but the 

 same elements can be distinguished in it as in Balcena. 



But the most distinctive feature in the malleus of Physeter is the suppression of the 

 projecting tubercle which in other Cetacea bears the homologue of the manubrium and 

 the insertion of the tensor tympani. On the anterior aspect of the head is a sharp, pointed 

 tubercle (pm) looking directly upwards ; directly below it is a very small blunt projec- 

 tion, pointing, in some specimens, a little forwards ; in most examples it is hardly per- 

 ceptible. This {mn) is the representative of the manubrium, and is much better deve- 

 loped in some of the Ziphioid Whales shortly to be described. In specimen No. 1584, 

 Physiological Series, in the Museum of the Royal College of Surgeons, showing the 

 auditory apparatus of Syperoodon, where the malleus is very similar in form to the same 

 ossicle in Physeter, the insertion of the membrana tympani to the tubercle (mn, 

 PL LXII. fig. 35), and of the tensor tympani muscle into the upper process (pm), is well 

 displayed. Hence mn in figs. 34 & 35 is the representative of the manubrium in Phy- 

 seter and Syperoodon, whilst pm is the homologue of the processus muscularis. 



piece of whalebone only, is identical with the Caperea antipodal-urn, described in the B. M. catalogue from a solitary 

 tympanic bone. Gervais and Van Beneden consider Caperea antipodarum to be the same as their Balcena antipo- 

 darum, which they distinguish from B. australis, and rightly, so far as the mallei are concerned. 



