270 NEW YORK STATE MUSEUM 



mantle — fleshy membrane infolding the soft parts of mollusks and brachio- 



pods and building the shell 

 medullary rays — the " silver grain " or radiating vertical bands or plates of 



parenchyma in the stems of exogenous plants 

 medusa — a jelly fish 



membranaceous — pertaining to a membrane 

 mesial — central 



mesogloea — central, non-cellular layer in the body of coelenterates 

 meso-pores — irregular meshes or cysts on the intercellular spaces of certain 



bryozoa 

 mesotheca — median wall separating opposed cells in certain bryozoan 



fronds 

 raetastonia — underlip of Crustacea, composed of small pieces immediately 



below and behind the mouth 

 microcorallites — smaller corallites of a compound corallum 

 mold — any impression of a fossil, in rock matrix, external or internal 

 moniliform — resembling a necklace or string of beads 

 monocyclic — of a single cycle 

 monticuliporoids — corals belonging to the order Monticuliporidae having 



many points of resemblance with the bryozoa 

 monticules — elevated areas on the surface of certain coral and bryozoan 



colonies, commonly carrying larger apertures 

 mucronate — produced into a long pointed extension 

 mural pores — pores in the walls of the corallites of the Favositidae 

 muscle scar — scar in a shell marking the former attachm.ent of a muscle 



niacreous — pearly; the nacreous layer of shells is the inner smooth pearly 



layer 

 nariform — shaped like a nostril 

 nasute — projecting, nose-like 

 nettlecell — one of the nematocysts or stinging cells found covering the 



tentacles and other body parts of most Coelenterata 

 node — knob; usually considered as ornamental 

 nodose — bearing nodes or tubercles 

 nodulose — knotty, or having nodes 



obconical — inversely conical 



oblate — flattened at the poles 



obovate — inversely ovate or egg-shaped 



obsequent stream — a stream flowing down the inface of a cuesta, or 



toward the old-land, tributary to the subsequent stream which in turn 



flows into the consequent 

 occipital — applied to the posterior part of the cephalon of a trilobite 

 occipital furrow — transverse groove on the cephalon of trilobites, which 



separates the last or occipital ring from the rest of the cephalon 

 occipital ring — posterior division of the glabella of a trilobite cephalon 

 operculiform — resembling an operculum 

 operculum — lid or cover 



