572 MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 



PLATE LV. 



(Stage XII.) 



PIGS. 212-223. Transverse serial sections of the first larva of Alpheus saulcyl from the same indi- 

 vidual as Figs. 209-211, excepting Figs. 222, 223. x73. 



REFERENCK LETTERS. 



A. //, second antenna. 



ad. HI., adductor of inaudible. 



ag., green gland. 



a/., ant.ttnnnlar fiber-mass of brain. 



ao., ear. 



a.op., ophthalmic artery. 



Kg., branchiostegite. 



B.gl., gland-like body. 



/>'. ,s'., blood sinus. 



/;/., foregut. 



fi>., tibor-mass continiiod into cesophageal commissure. 



gf., anteunal liber-mass. 



its., lateral poticli of masticatory stomach. 



Lb., labrum. 



//., lateral fiber-mass of brain. 



Md., mandible. 



Mi/., mulgiit. 



Afy'., anterior lobe of midgnt. 



Mg'*.. lateral lobe of midgut. 



Mp., septum between anterior lobes of midgnt. 



M. S., masticatory stomach. 



Mt., metastoma. 



Mr. I, first maxilla. 



Mr/iil. I, first maxilliped. 



n. ay., antennal nerve. 



n.nn., antenniilar nerve. 



or., avm., oesophagesl commissure. 



of., anterior filier-iiians and transverse commissure of brain. 



/). ["., pyloric valve of masticatory atomach. 



at. a., sternal sinus. 



