544 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 



d. Arteries of the Pelvic Limb. 



The distribution of these in most respects resembles what obtains in Phoca, slightly 

 modified to correspond with the altered relations of the fleshy parts, agreeing therefore 

 more closely with Trichechus, where also caudo-calcaneal bands knit the heel well to- 

 wards the spinal termination. The continuation of the abdominal aorta upon the in- 

 ferior aspect of the tail, arteria sacra media, is noteworthy chiefly on account of a plexus 

 vasculosus coccygeus or so-called coccygeal gland. This structure is represented in the 

 Otary by an elongated somewhat cylindrical, yellowish, glandular-looking body, almost 

 an inch long and 02 broad. It is situate between the converging long median tendons 

 of the pubo- and ilio-coccygeal muscles, and is covered in part by the junctional raphe 

 of the levator ani. 



External iliac and tributaries. — The epigastric is a large artery, which underlying 

 the external and internal oblique muscles upon the surface of the transversalis and out- 

 side the rectus, traverses the abdominal parietes and forms a free inosculation with the 

 equally capacious internal mammary. 



The femoral artery, of very moderate calibre, on leaving the ilium, crosses out- 

 wards almost at a right angle from it, and in this way traverses the groin to the 

 inner and here posterior edge of the femur. The artery, with its companion vein and 

 nerves, have the following relations before penetrating the adductor magnus muscle. 

 The psoas tendon is superficial to it ; the rectus femoris and sartorius lie anteriorly, 

 the pectineus behind. These altogether form an elongated triangular space, the artery 

 crossing this diagonally from before backwards. Deeply the vessel lies on the tendon 

 of the iliacus, and then passes over the the adductor longus. At the lower third of 

 the shaft of the femur it goes through a small opening in the upper border of the 

 adductor magnus and reaches the posterior surface of the bone. 



The popliteal artery is very short, and, as usual, lies in the popliteal space ; but its 

 relations nevertheless are different, as the hamstring muscles are shifted downwards and 

 do not approach the knee-joint, while the gastrocnemius has but one inner broad 

 head of origin. On the inner side, then, it is enclosed superficially by the adductor 

 magnus, and deeply by the gastrocnemius, these two muscles stretching from the con- 

 dyloid ridge of the femur to the head of the tibia. On the outer side is the remarkably 

 low insertion of the obturator externus, the upper portion of the biceps femoris, and 

 the soleus. Having reached the inner side of the head of the fibula, the popliteal di- 

 vides into anterior and posterior tibial arteries. 



This last-mentioned vessel rests on the popliteus and tibialis posticus, the long hallu- 

 cial and digital flexor muscles in part covering it to the turn of the heel. The internal 

 plantar artery appears to be that which furnishes the digital branchlets, or what here 

 represents the plantar arch. It results that the distribution of the plantar is uncom- 

 monly like that of the palmar vessels. The innermost artery runs alongside the hallux 



