194 ANATOMICAL TEGHNOLOOT. 



§ 573. Errors of Interpretation. — When an author denies the existence of a part the 

 presence of which is afiBnned by other writers, the discrepancy may be due to either of 

 five causes : — 



1. Its absence is the rule, and its presence in the other cases was exceptional. 



2. It was absent, though normally present. 



3. It was present, but accidentally overlooked. 



4. It was observed but not recognized, or was mistaken for some other part. 



5. It was seen, but purposely ignored. 



Of course the last named explanation is also the last to be entertained, but either of the 

 other four contingencies is liable to occur with even experienced dissectors and learned 

 anatomists. 



For example, the M. entopectoralis (Hg. 72), "pectoralis minor," is said by Straus-Durck- 

 heim (A, II, 336), and implied by Meckel (A, TI, 249), and Mivart (B, 145), to be wanting 

 with the cat ; its existence in any Carnivora is also denied by Cuvier (A, I, 370), and A. H. 

 Young (1, 171). Owen, however, speaks (A, III, 50), of the "pectoralis minor of the dog," 

 and its presence in that aniraal is admitted by Haughton (115) and Wood (T, 53), as it is 

 in the cat by the senior author, who refers (20, 306) to it as found in all the Felidae and 

 Canidae examined by him. 



The muscle considered by the writers last named to represent the " pectoralis minor " 

 of man is so large in most Carnivora that it was not recognized by the five writers first 

 named as the representative of that rather insignificant muscle ; in the bear and skunk, 

 however, as stated by the senior author in the paper referred to, it is again smaller than 

 the M. ectopeetoralis. 



In illustration of the second case, the M. supinator longus (Fig. 74) is said by Meckel 

 (A, VI, 303), and Huxley (A, 355) to be wanting with the dog. Chauveau, however, 

 aiErms (A, 390) its presence in dogs of all breeds, and it has been repeatedly observed by 

 the senior author. Hence we may conclude, provisionally at least, that it was exception- 

 ally absent in the individuals dissected by Meckel and Huxley. 



THE TECHNICAL TERMS OF MYOLOGY. 



§ 573. Musculus — Muscle. — The name for a mass of muscular 

 fibers. Such a muscle may or may not be a true muscular integer. 



What constitutes a muscular integer has not been determined ; as stated in the senior 

 author's brief discussion of the subject (10, 63), the phrase "morphological integer" 

 seems to have been first used vrith reference to the muscles by Coues (1, 233), but the gen- 

 eral question is discussed, directly or indirectly, by Owen, Parker, Spencer, and more 

 recently, Humphrey (E). In the present work, it has seemed best to us to recognize as 

 separate muscles, or as distinct divisions of muscles, all the muscular masses whose origins 

 and insertions are fairly constant and capable of definite description. 



In applying separate names to the divisions of the human trapezius (Fig. 66, § 607), 

 and deltoideus (Fig. 66, § 674), and yet treating the long and sliort lieads of the coraeoideus 

 (Fig. 75, § 668), as a single muscle, we are certainly open to the charge of inconsistency. 

 In the present transitional state of opinion respecting muscular integers, entire consis- 

 tency is hardly to be expected. 



§ 574. Muscular Groups. — It is sometimes convenient to speak 

 of two or more muscles collectively as a group, as, e. g., the pecto- 

 ralis group, the trapezius group, the triceps group. 



