638 Proceedings of the Royal Irish Academy. 



and fourth metatarsal bones were also noted (one example of each). 

 These anomalies were all furnished by a series of forty cases specially 

 examined. Some other similar rariations I have also from time to 

 time noted, without making any record of their relative proportion. 



Peronceus accessorius. — This name has been given to an accessory 

 origin of the peronseus longus. I have met with two well-marked 

 examples, each in the form of a muscular sHp, about two and a-half 

 inches in length, and a line and a-half in thickness, arising about the 

 middle of the fibula between the long and short peronsei. 



PeroncBus Irevis. — lu the origin of this muscle I have noted 

 no marked peculiarity except that of origin, as mentioned under the 

 head of peronaeus longus. In a good many cases a tendious prolonga- 

 tion was given to the origin of the short flexor of the little toe. A 

 slip to the extensor tendon of the little toe was present six times in 

 forty. In each case it arose either opposite to the external malleolus 

 or immediately in front of it. A slip of corresponding origin was in 

 one case united with the tendon of the fourth dorsal interosseous muscle, 

 and in another was found to be inserted into the dorsum of the fiith 

 metatarsal bone about its middle. 



Peronceus quartus. — Of this muscle I have already recorded the oc- 

 currence of two specimens. I have since met with a third, having 

 similar attachments to the others, but larger. In this case it pre- 

 sented the additional peculiarity of sending a second tendon to the 

 outer surface of the os calcis behind the insertion of the other. An 

 analogous structure has been described by Professor W. Krause. 



Pero7iceus quintus. — Having a similar origin to that of the muscle 

 last described, and joining the tendon of extensor digitcrum longus for 

 little toe. One specimen came under my notice last session. 



Extensor Irevis digitorum. — Twice in forty cases I found this muscle 

 give a delicate tendon to the little toe, joining the expansion of the 

 common extensor. In one of these the tendon to the great toe was 

 absent, and I have noted this peculiarity in several other instances. In 

 two cases a small slip was sent to the tendon of the fourth dorsal 

 interosseous muscle : one to that of the third, and one to that of 

 the first, have also been noted — a single example of each. 



Indicator pedis. — An independent muscular band, arising from the 

 dorsal surfaces of the astragalus and scaphoid bones ; and inserted into 

 the extensor tendon for second toe. This I have twice met with. 



Gastrocnemius. — Accessory fibres of origin of this muscle from the 

 external lateral ligament of the knee-joint have been already re- 

 corded (five examples). 



Gastrocnemius tertiiis. — This accessory third head of gastrocnemius 

 has come twice under my notice during last session. One arose from the 

 tendon of the biceps f emoris ; the second from the inner division of the 

 linea aspera, two inches above the knee-joint. Two other instances, 

 each from the planum popliteum, have been already published. 



Plantaris. — This muscle was absent three times in forty subjects 

 examined. The average frequency of the deficiency is ten per cent. 



