A Discussion on the Significance of Muscular Anomalies. 57 



2. Increase or development of parts that are rudimentary or retro- 

 graded, M. epitrochleo-anconeus, M. coraco-brachialis inferior, Supra- 

 condyloid process, lumbar ribs &c. Those without significance are: — 

 ]. Reduplication of parts, Polydactylism. 2. Anomalies of vessels by 

 occlusion and anastomosis. 3. Persistence of foetal conditions, hare 

 lip &c. Anomalies or injuries of foetus. 



Professor Patterson said that valuations unfavourable for the animal 

 are expected to disappear. Hare-Lip, Cleft Palate, and Spina Bifida 

 are not examples of true ontogeny. Dr. Lawrence showed recently 

 a kidney and ureter still separate. This tends to prove that these 

 parts were at one time developed separately to unite afterwards. 

 Professor Patterson said that twins might be taken as 1. Examples 

 of an increasing fertility that tended to improve the gaiety of nations 

 or 2. a reversion to a primitive type where paired young occurred or 



3. an exaggeration of such a condition as double digits, parasites like 

 Laloo &c. There is no necessary connection between variation and 

 specific alteration, variations have no power, per se, to produce specific 

 alterations. Meckel's diverticulum is the result of a change in the 

 developing organism. One may compare the numbers of occurences of 

 two opposite variations, and assign to the variation with the greater 

 number the name "winning type variety". The teeth in man seem to 

 be diminishing in number, shape, and size. The wisdom teeth seem 

 to be diminishing in size and there are more cases of fewer teeth 

 than more. There are also fewer teeth in man than in other animals. 

 So there is an obvious diminution in the size and quantity of the hair. 

 Patterson finds that there are as often 25 presacral vertebrae as 23 

 and the arrangement in apes is without precision. The limits between 

 which an organ can vary are very limited. Muscle anomalies do not 

 give any key to the development of the muscle system and afford but 

 scantly evidence of race History. The arrest of development of the 

 diaphragm suggests an association with reptiles but may not be ata- 

 vism. So excessive segmentation may not mean a progressive ten- 

 dency. Vascular abnormalities, leaving out the large vessels, are due 

 to anastomoses, and obstruction. The middle sacral artery may be a 

 sacral aorta or an artery formed by the union of segmental Arteries. 



