GLOSSARY. 8 1 



Membra'na preforma'tiva (L. preformed membrane). A deli- 

 cate membrane said to cover the dental pulp before the 

 calcification of the teeth. 



Membra'na pro'pria (L. special membrane). The basement 

 membrane of secreting organs. 



Membra'na pupilla'ris (L. pupillary membrane). A delicate 

 membrane by which in the foetus the pupil is closed. 



Membra'na saccifor'mis (L. sac-shaped membrane). The syno- 

 vial membrane of the fore-arm. 



Membra'na semiluna'ris (L. semilunar membrane). A mem- 

 brane attached to the septum in the syrinx of birds. 



Membra'na tym'pani (L. membrane of the drum). The mem- 

 brane which closes externally the tympanum or drum of 

 the ear. 



Membra'na tympanifor'mis inter'na (L. internal drum-shaped 

 membrane). The inner wall of that part of the bronchus 

 of birds which forms part of the syrinx. 



Membra'na velamento'sa (L. covering membrane). A mem- 

 brane in the internal ear. 



Mem'brane cos'to-cS'racoid. A layer of fascia attached supe- 

 riorly to the clavicle, and inferiorly to the coracoid process 

 and first rib. 



Menin'geal (Gr. mentnx, a membrane). Applied to certain 

 arteries and veins of the neck. 



Menis'cus (Gr. meniskos, a half-moon). A disc into which the 

 fibro-cartilaginous rings which connect the presacral ver- 

 tebras in birds are continued. 



Men'stmation (L. mensis, a month). The periodical uterine 

 discharges. 



Men'tal fora'men (L. mentum, the chin ; foramen, an opening). 

 An opening in the lower jaw through which the inferior 

 dental nerve and artery pass. 



Men'to-hy'oid muscle (L. mentum, the chin; Gr. filicides, 

 hyoid bone). An occasional muscle passing from the body 

 of the hyoid bone to the chin. 



Men'to-Mecke'lian element (L. mentum, the chin). The 

 portion of Meckel's cartilage which ossifies to form the 

 chin. 



Men'tum (L. the chin). The front median plate of the labium 

 in the Insecta. 



Meroblas'tic (Gr. meres, a part ; llastos, a germ). Applied to 

 those ova of which only a part of the yolk undergoes 

 segmentation. 



