430 TRANSACTIONS OP SECTION D. 



propria and the trigonica. Sometimes this bone is divided into a posterior tibial 

 and an anterior fibular piece ; if the division be due to fracture it is hard to tell 

 by Rontgen rays the difference. It may be an epiphysis, a separated process or a 

 migrant os trigonum. Putting to one side the statistics of fracture given by 

 Lilienfeld (quoted by E. Bibergeil in ' Zeitschrift fur Aerztliche Fortibildungen '), 

 it may be said that pathological deposits may occur owing to degeneration ; but 

 the os trigonum should show surface for articulation. 



An os tibiale externum is a sesamoid bone belonging mainly to the tibialis 

 posticus. It is more often found in women than men (unlike the os trigonum). 

 It may, if large, be in relation with the tains, and navicular, or (2), if smaller, 

 with navicular alone, or (3) it may be imbedded in soft parts and be in relation 

 with neither. It is sometimes like exostosis of navicular (Pfitzner). It may 

 be fused to navicular, and the talus may slide over its cartilage or membrane- 

 covered surface. 



Gruber saw the tuberosity drawn out in 10 per cent, of the examples. 

 Jaboulay believed that the os tibiale externum was an epiphysis of navicular and 

 joined to it by cartilage. Waldeyer figures four cases of os tibiale externum 

 which are found near the tuberosity or in place of it. V. Bardeleben says this 

 bone is a sixth toe-ray to be homologised with the tibiale of Gegenbaur. 

 Waldeyer is of opinion that the name has been used in different senses by diffe- 

 rent authors. Three of these were typical skeletal parts. Some examples are to be 

 regarded as ossification of tendons or ligament. The recognition of the bone is 

 of the greatest importance by palpation or Rontgen rays. The sesamium pero- 

 neum lies in the postero-lateral end of the cuboid bone (oblique eminence). It 

 is ossified cartilage and is better seen in the lower apes, and oftener, than in 

 man. It is sometimes seen well in the chimpanzee. It is sometimes imperfect 

 or degenerate. An os intermedium tarsi is also found in the dorsal side of the 

 first interosscus space. It is apt to be pointed and cartilaginous and articulates 

 with cuneiform I, and metas I and II. Gruber found this bone anchylosed to 

 one of the adjacent bones. The os vesalianum is found rarely, and between the 

 fifth metatarsal and cuboid and articulating with these. It may have an inde- 

 pendent ossific centre and afterwards unite to metatarsal V, or it may coalesce 

 before bone is laid down. This ossicle may be confused with a fracture frag- 

 ment. Dwight found a secondary cuboid and a secondary calcaneum. He uses 

 the Rontgen rays to examine wrists and ankles after the superficial parts are 

 removed. 



The possibilities of these ossicles occurring in the foot prove, for some, that 

 the lower extremity has still in the course of its development the elements of 

 change, and, though the Caucasian's foot is specialised, yet retrogressive meta- 

 morphoses may be possible. It is certainly true that just as the left hand is 

 susceptible of training, the training of this limb and that of the lower limbs by 

 means of evolutions may be attended with the greatest advantage to man. 



WEDNESDAY, SEPTEMBER 6. 



The following Papers were read :— 



1. On the Renal Organs and some other Features of the Internal Anatomy of 

 Squilla. By W. N. F. Woodland. 



In view of the isolated position of the Stomatopoda (the group without doubt 

 having arisen from the base of the Malacostracan stem), the large size and 

 high development of the principal genus Squilla, and the statement made by 

 Kowalevsky that the renal organ is a maxillary gland, it is remarkable that this 

 structure has, up to the present, attracted so little attention. One might have 

 anticipated that, the researches of Marchal, Grobben, Kingsley, and others having 

 demonstrated the high degree of complexity attained by the antennary gland in 

 the higher Malacostraca, some curiosity might have been felt respecting the 

 development of the other pair of renal organs found in Malacostraca almost as 



