8 2 GLOSSARY. 



MerS'cerite (Gr. mcros, the thigh ; kcras, a horn). One of the 



joints in the antennae of the Crustacea which represents 



the tneropodite of the typical Crustacean appendage. 

 Meroistic (Gr. meros, a part; don, an egg). A term applied 



to the ovaries of insects when they secrete not only ova, 



but also vitelligenous cells. 

 Mero'podite (Gr. mcros, the thigh, ham ; pous,podos, a foot). 



The fourth joint of the typical appendage in the Crustacea. 

 Merosto'mata (Gr. meros, a part; stdma,<a mouth). A division 



of the Crustacea. 

 M6senc8'phalon (Gr. mhos, middle; enkcphalon, the brain). 



The part of the brain which is developed from the middle 



cerebral vesicle of the embryo, and which comprises the 



corpora quadrigeminaorbigemina,crura cerebri, and the itcr. 

 Me'senteries (Gr. mesos, middle ; enteron, an intestine). The 



vertical partitions which divide the space intervening be- 

 tween the alimentary tube and body-wall of a sea-anemone 



into chambers. 

 Me'sentery (Gr. mesas, middle ; enteron, an intestine). The 



fold of the peritoneum which connects and supports the 



intestines. 

 Me'soblast (Gr. mhos, middle ; blastos, a germ). The middle 



layer of the blastoderm. 

 Mesobran'chial (Gr. mesos, middle; bronchia, a gilH A term 



applied to a region in the carapace of the Brachyura, 



which covers the mid-branchial region of the body. 

 Mesocae'cum (Gr. mesos , middle). A fold of the peritoneum 



formed in some cases behind the caecum. 

 Mesoce'phalon (Gr. mesos, middle; kephale, the head). A 



name sometimes applied to the Pans Varolii. 

 Mesoco'lon (Gr. mhos, middle). A fold of the peritoneum 



behind the colon. 

 Me'sodenn (Gr. mesos, middle ; derma, skin). The middle 



body-layer in some Invertebrata. 

 Mesogas'tric (Gr. mhos, middle ; gastcr, the stomach). The 



middle gastric lobe of the carapace in the Brachyura. 

 Mesogas'trium (Gr. mhos, middle; gaster, the stomach). A 



membranous fold by which in the foetus the stomach is 



attached to the vertebral column. 

 Mesono'tum (Gr. mhos, middle; notos, back). The tergal 



portion of the mesothorax in the Insecta. 

 Mesophlce'um (Gr. mcsos, middle; phloios, bark). The middle 



layer of the bark. 



