127 Mes 



Meroblastic. — The term given to eggs which undergo 

 a partial segmentation. (Gr. meros, a part and 

 blastos, a sprout.) See Partial segmentation. 



Mesenteron.^ — A short thin tube following the 

 gizzard which connects the original anterior 

 and posterior invaginators of the embryo. 

 The mid gut comprising only the stomach. 

 (Gr, mesos, middle, and enteron, intestines.) 



Mesepimeron. — [See Mesepisternum.] 



Mesepisternum. — One of the two elements placed 

 on each side of the thorax of Ants, between the 

 mesonotum and the mesosternum ; the other 

 element is the mesepimeron. The mesepi- 

 sternum is placed ventrally while the mesepi- 

 meron is dorsal. (Wheeler.) (Gr. mesos, 

 middle, and epi, on, and sternum.) 



Meso. — A Greek prefix signifying the middle. 



Mesoblast. — (Gr. meso, and blastos, a sprout.) See 

 Mesoderm. 



Mesoderm, or Mesoblast. — The middle embryonic 

 cell-layer lying between the endoderm and the 

 ectoderm. (Gr. meso, and derma, skin.) 



Mesodermal Streaks. — (Embryol.) The two lateral 

 streaks formed by the mesoderm dividing, due 

 to the withdrawal of its cells from the median 

 line. 



Mesonotum. — The upper surface of the mesothorax. 

 (Gr. meso, and notnm, from notos, the back.) 



