COMMON FINBACK \YHALE. 185 



feet (2.99 meters) for the greatest girth or the diameter. Applying these figures in the formula 

 he obtained 45.8 tons or 45,800 kilo for the weight, which accords remarkably with Murie's 

 figure for a 60-foot Finback. According to Wilcox, the 60-foot whales killed in the Gulf of 

 Maine in 1885, weighed about 25 tons each, but it is not stated how this figure was obtained. 



Auditory Apparatus. — An interesting recent account of the internal ear is given by Lillie 

 (1910, p. 775) who dissected this organ in an adult Finback taken on the Irish coast. The 

 auditory canal is continued backward from the minute external opening until it reaches the 

 posterior border of the squamosal bone. It then turns inward, and with slightly increased 

 diameter (1.5 inches) follows along the posterior edge of the squamosal to reach the tympanic 

 membrane, which, curiously, is sac-like in shape somewhat like the finger of a glove. This 

 sac is about four inches long; its blind end lies in the auditory canal, and its open end joins 

 the wall of this canal, and by a ligament connects with the malleus, which is fused with the 

 oval tympanic bone. The semicircular canals in the middle ear are present but small. The 

 eustachian tube is about one foot in length and connects the cavity of the pterygoid fossa 

 with the chamber at the junction of the nasal passages. There is a large plug of ear wax in 

 the tube of the external auditory meatus. It is not certain that sound is received through the 

 car, though the tympanic bones may respond to vibrations through the water. Lillie suggests 

 that the curious tympanic membrane, shaped like a glove-finger, may act as a pressure gauge, 

 by coming in direct contact with water in the external ear passage, and thereby apprise the 

 whale of its near approach to the surface when it rises to spout. 



Musculature. — The muscular anatomy of the Finback Whale probably differs little in gen- 

 eral from that of the Little Piked Whale as described by Carte and MacAlister (1868). 

 Delage (1885) describes the large panniculus which covers all the anterior half of the lower 

 portion of the body, beginning anteriorly on the arch of the jaws and extending back to the 

 umbilicus. It thus corresponds roughly with the area of the external plicae. Superficially it 

 is strongly united to the blubber, especially on the throat where it seems inserted into the 

 skin, and by aponeurosis. 



Struthers (1871, p. Ill) seems to have been the first to make a careful dissection of the 

 muscles of the hand. These are reduced to three on the inner or flexor aspect and a single 

 one on the outer or extensor aspect of the hand. The latter corresponds to the extensor com- 

 munis digitorum. It arises froin the inner aspect of both radius and ulna and from the apo- 

 neurosis between them. It becomes tendinous, and opposite the middle of the carpus sends 

 off four tendons, one to each digit. Of the three flexor muscles, the flexor car-pi ulnaris has 

 the usual relations, arising from the olecranon cartilage and ulna near it, and inserting by 

 tendon into the pisiform cartilage. The flexor digitorum ulnaris is the largest of the muscles, 

 arising along the center of the forearm, partly from the end of the humerus, ulna, and inter- 

 osseous tissue. Its tendinous expansion finally gives off four branches one to each digit, l)ut 



