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



in Physeter and Syperoodon, The head is better developed than in either of those 

 Whales. It is half as long again horizontally as vertically, whilst in Syperoodon 

 this portion of the ossicle, though not more prominently convex than in JBerardius, is 

 almost a hemisphere. It rises very prominently above the facets. The depression on its 

 outer aspect is small and slit-like ; the process holding the ossicle to the tympanic bone 

 is as short as in the Physeteridge already described, and made up of the same elements 

 (compare PL LXIII. fig. 1 with figs. 13 & 14). The specialized modifications in the 

 processus muscularis and manubrium are very marked in the malleus of Berardius. The 

 processus muscularis (fig. 1, pm) is nearly as long as in Physeter, so that it is better 

 developed than in Syperoodon. Here it may be observed that it is only in the Phy- 

 seterida? that the processus muscularis can be found as an actual process among the 

 Cetacea, since in the Whalebone Whales and Dolphins its homologue is either a rough sur- 

 face or a depression on the tubercle, from which also springs the manubrium ; but it is this 

 very tubercle which is wanting in the Cachalots and Ziphioid Whales, where the processus 

 muscularis is distinct. 



In Berardius the manubrium is much better developed than in Syperoodon or 

 Physeter. It is seen as a small, sharp spine *, arising close to the root of the processus 

 muscularis, and running directly downwards, whilst the other process runs straight 

 upwards. The two processes together lying close against the head, resemble the con- 

 trivance seen on board ship for belaying cable. The articular surface is extensive even 

 in proportion to the rest of the malleus; its upper facet is of the same form as in 

 Syperoodon, plane, and very elevated at its margin; the lower is smaller and convex, 

 everted as in the Ziphioid Whale just mentioned. 



Hence, in its malleus, Berardius is more perfectly specialized than either Physeter 

 or Syperoodon. This ossicule is certainly, among these three Whales, largest and 

 bulkiest in Berardius, smallest, proportionately, in Physeter, owing to the ill-develop- 

 ment of the portion of the head external to the facets in that animal. 



The incus (PI. LXIII. fig. 1) resembles that of Syperoodon rather than Physeter ; the 

 processus " brevis " is still longer, more divergent, and flattened and expanded at its 

 extremity. Close to its root the body (as is the case in Syperoodon) is not so reduced 

 and shallow as in Physeter; the groove dividing the facets is not very sharp in 

 Berardius. The processus longus is quite similar in character to that of Syperoodon. 

 ■ The stapes is longer than in the other Physeteridse here described. In the College 

 specimens there is a prominent tubercle on the inner aspect of the head for the tendon 

 of the stapedius. The crura are long, stout, and straight, a slit-like but pervious aperture 

 divides them. The base is narrow, its margin is rather thick, and it is quite concave 

 towards the vestibule. 



I have examined the malleus and incus from a skull of Mesoplodon hectori in the 

 British Museum. These bones are much smaller than their representatives in the above- 

 described Physeteridse. The malleus has a head as small as in Physeter, moderately 

 convex, and produced backwards to a prominent blunt point. The head projects slightly 

 above the facets, as in Syperoodon ; the articular facets are proportionately still smaller 



* l'l. LXIII. fig. 1, where this spine is lettered hm in place of mn, its true homologue. 



