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ON THE ANATOMY OF SCOPUS UMBRETTA. [Nov. 18, 



families by the presence or absence of the ambiens ; and the fact 

 that Scopus umbretta has not the ambiens, but has the semitendinosus, 

 its accessory, and the femoro-caudal, is no clear indication of its 

 affinities with either. In the condition of the pectoral muscle, 

 however, Scopus decidedly agrees with the Ardeidae and differs from 

 the Ciconiidae. 



The disposition of the deep plantar tendons is not characteristi- 

 cally " Ciconiine." In all the Herons and Storks dissected by Prof. 

 Garrod the tendon of the flexor longus hallucis sends down a vin- 

 culum to join the tendon of the flexor perforans digitorum before 

 the trifurcation of the latter, the vinculum being extremely slender 

 in the Herons and altogether absent in Botaurus stellaris. I find, 

 however, that the condition of the deep plantar tendons in Scopus 

 is exactly repeated in Ciconia nigra. In this bird Mr. Forbes ' has 

 figured a precisely similar arrangement to that which I have de- 

 scribed in Scopus ; the tendon of the flexor hallucis sends off a 

 special slip to digit n. as well as a vinculum to the flexor perforans 

 just before its trifurcation. 



In the absence of the expansor secundariorum, Scopus agrees with 

 Cancroma and Egretta 2 and the Ciconiidae ; this muscle is present in 

 all Herons except the two genera mentioned. 



The tendons of the patagium do not differ much from what is 

 found in other Herodiones ; the absence of a biceps slip is charac- 

 teristic of both Storks and Herons. 



The muscular anatomy of Scopus, on the whole, appears to com- 

 bine the characters of both the Ciconiidae and the Ardeidae. On 

 myological grounds only it would be difficult to assign it definitely to 

 either group ; in fact, the only features in which this genus espe- 

 cially resembles the Herons and differs markedly from the Storks are 

 the form of the syrinx and the air-sacs, while, as already stated, the 

 arrangement of the feather-tracts and the structure of the skeleton 

 are more particularly Stork-like. It is clear, therefore, that Scopus 

 is in many respects an intermediate type between the Ciconiidse on 

 the one hand and the Ardeidae on the other ; and its relation to 

 both may be seen at a glance from the accompanying table : — 



Pectoral muscle 



Ambiens 



Deep plantar tendons 



Expansor secunda- 

 riorum. 



Origin of obturator 

 internus. 



Syrinx 



Caeca 



Scoptis umbretta. 



Not completely double. 



Absent. 



fl. h. with a special slip 

 to dig. ii. and a vin- 

 culum. 



Absent. 



Oval. 



With intrinsic muscles; 

 anterior rings of bron- 

 chi incomplete, closed 

 by membrane. 



Herons. 



Not completely double. 



Absent. 



fl. k. with slender vin- 

 culum only, some- 

 times absent. 



Absent (except in Can- 

 croma and Egretta). 



Triangular. 



With intrinsic muscles ; 

 anterior rings of bron- 

 chi incomplete, closed 

 by membrane. 

 1. 



Storks. 



Completely double. 



Earely absent. 



fl. h. with special slip to 

 dig. n. ; a vinculum 

 (in Ciconia nigra). 



Present. 



Oval. 



Without intrinsic mus- 

 cles ; rings of bronchi 

 complete. 



2. 



MSS. 



2 Garrod, Coll. Papers, p. 329. 



