131 



24. An instance of the extensor carpi radialis accessorius of Wood I 

 found in both arms of a muscular male, arising behind the extensor 

 carpi radialis longus by a flat, fleshy belly, which ended in a fine ten- 

 don, that, becoming fleshy, was inserted into the outside of the first 

 phalanx of the thumb, outside the abductor pollicis. This muscle was 

 digastric, as was also Mr. Wood's instance ; and notes of another speci- 

 men of the same kind were given to me by Dr. Richardson, of Dublin. 



25. A distinct scansorius muscle occurred in one instance posterior 

 and parallel to the tensor vaginae femoris, but much more deeply seated, 

 separated from the anterior border of the gluteus minimus, and inserted 

 into the anterior and inferior portion of the root of the great trochanter. 

 This muscle, homotypically, is of great importance, and is one whose 

 affinities have been often mistaken ; it has been frequently confounded 

 in comparative anatomy with another muscle, which we should con- 

 sider as a perfectly diverse element. I refer to the iliocapsular, or 

 opponens quadrato-femoris. To the scansorius type should be referred 

 the muscle described by Professor Haughton as opponens quadrato- 

 femoris in the ostrich, "Proceedings of the Royal Irish Academy," 

 1864, figs. 6 & 7, p. 17; as also the muscle described by the same 

 author as iliocapsular in the lion, "Proceedings of the Royal Irish 

 Academy," May, 1864, fig. 14, p. 30. Prom the true scansorius type 

 the iliocapsular differs in several respects : firstly, that in the former 

 the origin is dorsal, while in the latter it is ventral, or marginal; 

 secondly, that the point of insertion in the former is on the outer, 

 or exotrochanteric aspect; while in the latter it is in the neighbourhood 

 of the lesser trochanter. 



26. The peroneus quarti metatarsi, arising from the front of the 

 fibula for its lower fourth, and inserted into the base of the fourth 

 metatarsal bone, has been present as a separate muscle three times 

 without any peroneus tertius. Pour times it has co-existed with it 

 nearly separate from the last muscle for its entire extent. In two 

 cases the peroneus tertius, quarti metatarsi, and quinti digiti co-existed ; 

 and in one the peroneus longus, brevis, tertius, quartus (Otto), quarti 

 metatarsi, and quinti digiti, were all present. The peroneus quarti 

 metatarsi in another instance was represented by an offshoot from the 

 outer tendon of the extensor longus digitorum, and it always passed in 

 the same sheath of the annular ligament as that tendon. The nomen- 

 clature of these muscles is a little confusing, and this muscle would be 

 much more correctly designated peroneus quartus; but Otto (Neue 

 seltene Beobacht.) has applied this name to a muscle to be referred to 

 below, and even the name peroneus quarti digiti is used by Messrs. 

 Murie and Mivart to represent a muscle in Lasyprocta cristata, "Pro- 

 ceedings Zoological Society," 1866, p. 405, springing from the site of 

 the origin of the peroneus brevis, and passing to be inserted into the 

 first phalanx of the fourth toe. I have therefore applied the name used 

 above as its most correct exponent. 



27. The peroneus quinti digiti I have found very frequently pre- 



%. I. A. PEOC, VOL. X. j; 



