THE PHOCID^. 363 



nens of the fifth digit. A special long abductor of this digit, 

 however, passes from the olecranon to the distal phalanx. The 

 iliacus is wanting, and there is no psoas major / but muscles 

 which represent the psoas minor and the subvertebral muscles 

 of the Cetacea are very large and play an important part in 

 effecting the locomotion of the Seal. The pectineus is very 

 small, and the other adductors are inserted, not into the femur, 

 but into the tibia. The glutceiis maximiis is inserted into the 

 whole length of the femur. The seini-meinbranosus and seini- 

 tendinosus are replaced by a caudo-tibialis, which arises from 

 the anterior caudal vertebras and is inserted into the tibia, 

 some of its tendinous fibres extending to the plantar aspect 

 of the hallux. The poplitmus and gastroc7iemius are strong, 

 but there is no solmus. The tendon of the pkmtaris passes 

 over the calcaneum and ends on the plantar fascia of the per- 

 forated tendon of the fourth digit. The other perforated ten- 

 dons seem to arise from the fascia attached to the calcaneum. 



The dental formula is ^. ^^ c. -^^ m.p.m. ^5 =: 34. 



The grinding teeth have triangular crowns with notched 

 edges, and at most two fangs. 



The milk-teeth are shed during foetal life, and at this 

 period there are three molars above and below on each side, 

 which appear to be replaced by the second, third, and fourth 

 of the adult set. If such be the case, only the hindermost of 

 these last will be a true molar. 



The tongue is bifid at the extremity. The oesophagus, 

 very wide and dilatable, passes without any very well-marked 

 line of demarcation into the stomach, which is a great pyri- 

 form sac w^ith its pyloric end bent upon itself. The intestine 

 is about twelve times as long as the body. The colon is 

 short, and is provided with a caecum. The liver is divided 

 into a great number of lobules, which are, as it were, set upon 

 the inferior cava. The latter vessel, just below the diaphragm, 

 presents a great dilatation, into which the vence hepaticce oi 

 the several lobules open. After traversing the diaphragm, 

 the vena cava is surrounded, for about an inch, by a layer of 

 red circular muscular fibres. The aorta and the pulmonary 

 artery are both dilated at their commencements. 



The penis of the male is contained within a prepuce, sup- 

 ported by a loop of the cutaneous muscle. There is a large 

 OS penis, which presents a groove for the urethra inferiorly. 

 The prostate is small, and there are no vesiculjB nor Cowper's 

 glands. The testes lie just outside the inguinal canal. The 



