164 DB. li. C. A. WINULE AND MK. 1\ G. PARSONS ON THE [Mar. 1, 



are often reinforced by some of the lower fibres of the semitendi- 

 nosus. AVe do not propose to lay any stress on the presence or 

 absence of the caudal head, since it is so difficult to determine 

 whether it should be included with the ectogluteus or not, and we 

 are uncertain what views other observers have taken of it. 



Tenuissimug (Bicipiti accessorius). — This, as its name implies, is 

 a slender ribbon-like muscle which usually rises from the first 

 caudal vertebra and passes down the back of the thigh and leg, 

 deep to the biceps and superficial to the great sciatic nerve. In 

 the lower part of the leg it usually joins the lowest fibres of the 

 biceps and, with them, is conducted down to the calcaneum, 

 helping to ensheath the tendo Achillis. We should like here to 

 call special attention to this prolongation of the flexor lateralis to 

 the calcaneum with the teudo Achillis. The muscle passes over 

 three joints, being an extensor of the hip, a flexor of the knee, and 

 a plantar flexor of the ankle. It probably assists in the leaping- 

 powers of the animal possessing it. How far this continuation 

 downward is present in orders other than Carnivora we do not at 

 present know. 



The teuuissimus seems to be very constantly present among the 

 Carnivora, though, as it adheres somewhat closely to the deep 

 surface of the biceps, it is apt to be missed unless specially looked 

 for. In the following animals its presence was noticed and in no 

 case, with the exception of that of Cpudurns (12), is it definitely 

 stated that the muscle was absent: — Felis leo (1, 2, 3), F. tijris 

 (4), F. pardus (5, 6, 7), F. pardalis (8), F. catiis (9), Gryptoprocta 

 (13, 14, 15), Viverra (16, 17), Viverricula (19), Genetta (20, 23, 24), 

 Paradoxurus (25, 26), Herpestes (29, 30), Cynidis (31), Hycena 

 striata (36), apparently in Hijctna crocuta (37), Canis familiaris 

 (39, 41, 42, 43, 44, 45) (see fig. 1), C. aureus (50, 50 a), C. meso- 

 melas (51), Ursus americanus (58, 59), Frocyon lotor ((j'S, 64, 65), 

 in one specimen (65) Allen (XXVI.) records that the muscle rose 

 from the third trochanter ; A^«s-iea (68, 69), Oercoleptes {72), Galictis 

 (75), MusteJa (82), Mel^^s (85, 86), and Lutra (88, 90, 93). 



Quadriceps exteiisor. — The four muscles which make up the 

 quadriceps show little variety in the Carnivora. The rectus (super- 

 ficialis quadricipitis) is sometimes described as rising b_y one head, 

 sometimes by two, and it is interesting to note that in some cases 

 the straight head is said to be present, in others the reflected. In 

 the animals which we have ourselves dissected we have paid a good 

 deal of attention to this point, and we feel convinced that there is 

 no real suppression of either head, but that they rise very close 

 together, and that the interval between them is filled up by fibrous 

 tissue, thus giving the appearance of one broad origin. The 

 remaining three parts of the quadriceps — mesialis, lateralis, and 

 profundus — are more or less fused, but the lateralis (vastus externus) 

 always exceeds the mesialis (v. internus) in size. The profundus 

 quadricipitis (crureus) may rise from the whole of the shaft of the 

 femur, but more commonly it misses the upper fourth. 



Tibialis amicus. — This muscle rises from the upper two-thirds 



