DEVELOPMENT OF THE AMERICAN ALLIGATOR — REESE 63 



LETTERING FOR ALL FIGURES 



a, head-fold of amnion. 

 aa, anterior appendage. 

 ac, anterior cardinal vein. 

 al, allantois. 



an, anterior nares. 

 ao, aorta. 

 aop, area opaca. 

 ap, area pellucida. 

 ar, aortic arch. 

 au, auricle. # 



b, bulbus arteriosus. 

 be, body cavity. 

 blp. blastopore. 



bp, basilar plate. 

 bv, blood vessel. 



c, centrum of vertebra. 

 ca, caudal artery. 



ch, cerebral hemisphere. 



el, cloaca. 



en, cranial nerve. 



cp, posterior choroid plexus. 



cv, cardinal veins. 



■dc, ductus Cuvieri. 



e, eye. 



ec, ectoderm. 



cc' , thickening of ectoderm. 



en, entoderm. 



en' , endocardium. 



cnt, enteron. 



cp, epidermal layer of ectoderm. 



epi, pineal body. 



es, embryonic shield. 



f, fronto-nasal process. 



fb, forebrain. 

 fg, foregut. 

 g x S, gill clefts. 

 gf 1 - 6 , gill folds. 

 gl, glomerulus. 

 h, head-fold. 

 hb, hindbrain. 

 ht, heart. 



i. intestine. 



i', stomach. 



in, infundibulum. 



tr, iris. 



it, iter. 



fc, kidney (metanephros). 



/, remains of groove between second- 

 ary folds. 

 la, larynx (cartilages of). 



li, liver. 



//, lower lid of eye. 



In, lens. 



Ir, inferior rectus muscle of eye. 



lu, lungs. 



Iv, lens vesicle. 



m, mouth. 



ma, manus. 



nib, midbrain. 



me, medullary canal. 



me', tip end of medullary canal. 



md, mandibular fold. 



mes, mesoderm. 



incs', myocardium. 



mf, medullary fold. 



nig, medullary groove. 



mk, Meckel's cartilage. 



nip, muscle plate. 



ms, mesentery. 



mv, meatus venosus. 



nix, maxillary fold. 



myc, myocoel. 



n, nasal invagination or cavity. 



11a, neural arch of vertebra. 



nc, neurenteric canal. 



nl, nervous layer of ectoderm. 



nt, notochord. 



0, ear vesicle. 



oc, optic cup. 



oe, oesophagus. 



on, optic nerve. 



os, optic stalk. 



ov, optic vesicle. 



/>, pituitary body. 



pa, posterior appendage. 



pan, pancreas. 



pc, posterior cardinal vein. 



pe, pes. 



pg, primitive groove. 



p/i, pharynx. 



pi. pelvis. 



pn, posterior nares. 



pr, pericardial cavity. 



ps, primitive streak. 



pt, pecten. 



rt, retina. 



s, somites. 



sc, spinal cord. 



se, sphenethmoid cartilage. 



sf, secondary fold. 



