MR WM. TURNER ON VARIABILITY IN HUMAN STRUCTURE. 177 



flexor sublimis digitorum from the coronoid process of the ulna. This slip ter- 

 minated on a tendon, which in one specimen became blended with the tendon of 

 the flexor profundus passing to the middle finger ; in another with the tendon of 

 the same muscle going to the ring finger ; and in the third with the tendon going 

 to the little finger. In the fourth specimen the flexor sublimis was not connected 

 to the flexor profundus by any intercommunicating structures. In one specimen 

 the middle, ring, and little finger tendons of the flexor profundus were connected 

 together by a network of intertendinous bands ; in another such bands only con- 

 nected the middle and ring finger tendons of that muscle ; in the remainder these 

 structures were absent. In one of the specimens the abductor pollicis received a 

 distinct slip of origin from the styloid process of the radius, whilst in another the 

 abductor minimi digiti received a slender muscular slip, which arose in the lower 

 part of the forearm from an accessory palmaris longus tendon. 



It would be quite possible for me to multiply examples to serve as additional 

 illustrations of variations occurring in several of the most important organic sys- 

 tems in the same body, — variations so well marked, indeed, that though, as in 

 the cases above cited, it is probable no outward evidence of their existence was 

 manifested, yet they furnished the individuals in whom they occurred with cha- 

 racters as distinctive as any peculiarities of external configuration. Hence we 

 may conclude that in the development of each individual a morphological 



which is very frequently met with in some of the Mammalia. For there has now been recorded a 

 considerable number of instances in which a distinct canal, generally with bony walls, existed in this 

 locality in various Quadrumana, in Galeopithecus, in the Edentata and Monotremata, in many Car- 

 nivora, Marsupialia, Rodentia, and in some of the Pinnepedia ; whilst it would appear to be absent in 

 the Ruminantia, Solidungula, Multungula, and Cetacea. But though the canal would seem to occur 

 almost constantly in all the genera of some orders and families of the Mammalia, yet it by no 

 means follows that in other orders and families, though it may occur in one genus, that it exists in 

 all, or even though it may occur in one species of a genus, that all the species of the same genus 

 should possess it. Thus, as Professor Owen has shown (Article Marsupialia in " Cyclopaedia of 

 Anatomy and Physiology"), whilst it exists generally amongst the Marsupialia, yet it is absent in 

 Dasyurus and Thylacinus ; and though most of the species of Phalangista possess it, yet it does not 

 exist in Phalangista Coolcii ; and whilst Gruber saw it in Erinaceus auritus, he did not find it, and I 

 have not seen it, in Erinaceus europceus. In the Pinnepedia also it has been described by various 

 anatomists as present in the Phoca vitulina, and Gruber has seen it in other species of the same 

 genus. In a common seal which I dissected, I found that it only transmitted the median nerve, 

 neither the brachial artery, nor any of its branches passed through it ; in the Walrus (Trichechus), 

 however, anatomists agree in stating that it does not occur, a fact which I have observed in three 

 skeletons of that animal which have come under my observation. Again, in some of the Mammalia 

 variations in its occurrence take place in individuals of the same species, a circumstance which has 

 been noticed not unfrequently amongst the Quadrumana, though it has not as yet been seen, I believe, 

 in the humeri of any of the Anthropoid Apes. Thus, whilst Tiedemann describes it as present in 

 Cercopithecus sabceus and Cercocebus fuliginosus, Meckel and Otto state that it is wanting in those 

 species; a discrepancy of statement which may probably be explained by regarding the arrangement 

 as a variety present in one individual but absent in another. Of the skeletons of the Quadrumana 

 personally examined, I have found the foramen absent in two specimens of the Orang, in a Chim- 

 panzee, in two specimens of the Gibbon, in Cercocebus fuliginosus (agreeing thus with Meckel 

 and Otto), in Macacus cynomolgus, in Cynocephalus maimon, Hapale jacchus, and Ateles paniscus ; 

 whilst I have found it present in a species of Cebus, and in the prosimian Stenops tardigradus. 



