340 MR. A. H.GARROD ON THE [Apr. 4, 



modification of which, in the genus Cergle among the Aleedinidse, 

 has been described and figured by Dr. Cunningham in the Society's 

 1 Proceedings ' *. This, by the way, I may mention, I have had the 

 opportunity of fullv verifying. Meckel, in his ' General Treatise on 

 Comparative Anatomy,' tells ust that he found it at its minimum of 

 development in the Gallinse, the Goose, and tbe Cormorant. In a 

 specimen of Sulci fusca, as well as in Phalacrocorax carho, it is 

 present, but extremely small, I find. It is entirely absent in Plotvs 

 anhinga, the longus colli posterior (cervicalis ascendens, Meckel) 

 entirely ceasing at the lower margin of the axis vertebra, in the 

 tendon above described. 



There are other myological features deserving of special notice in 

 the thoracic and crural regions of the Darters. 



The great pectoral muscle is composed of two independent 

 layers : — a superficial large one, arising from the inferior border of the 

 sternum, its carina, and from the outer border of the furcula ; and a 

 deep one from the upper two thirds of the deeper part of the carina, 

 superficial to the pectoralis secundiis, and from the symphysial half 

 of the outer border of the furcula. The superficial layer is inserted by 

 a broad linear attachment to the pectoral ridge of the humerus, whilst 

 the deep layer ends in a rounded tendon which commences at the 

 axillary margin of the triangular muscle, with which it is associated, 

 and receives the fibres of the remainder of the muscle in its course 

 to its attachment into the lower end of the pectoral ridge of the 

 humerus, beyond the insertion of the lowest fibres of the superficial 

 layer. In Plate XXVII. this arrangement is clearly indicated. A 

 condition exactly similar to this is observed in Pha'ethon, Pelecanus, 

 Sulci, the Cathartidse, all the Storks, and the Petrels, and in no 

 other birds as far as I am aware. In Phalacrocorax it is not easily 

 recognized. 



As in Phalacrocorax and Pha'ethon, but not in Sula or in Pele- 

 canus, the biceps muscle of the arm sends a fleshy slip to the middle of 

 the patagial tendon of the tensor patagii longus (Plate XXVII. b. s). 



No trace of the expansor secundariorum\ muscle could be de- 

 tected. 



As in all the other Steganopods, the tensor fascia of the thigh 

 does not cover the biceps cruris in the least. 



The ambiens is of fair size ; it deeply grooves the large ossified 

 patella ; and some of the fibrous ligament overlapping this groove 

 shows traces of ossification ; so that in aged birds the groove may be 

 converted into a foramen, as is always the case in Phalacrocorax, 

 where the thus formed foramen is far from superficial (vide Plate 

 XXVIII. figs. 5, C, & 7). In a specimen of Pelecanus rufescens the 

 patella was not ossified. 



The semitendinosus is very large, composed of parallel fibres, and 

 without any accessory head developed to join it. The femoro-caudal 

 also, as in all other true Steganopods, lacks an accessorius ; it closely 



* P. Z. S. 1870, p. 280. 



t French edition, Paris, 1829-30, vol. vi. p. 11 



t Vide ante, p. 193. 



