568 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Pl.ATK LTTI. 



¥ni. 193. Part of trausverse sectiou tbrongh an embryo of Alpheus saulcyi, which is nearly ready 

 to hatch, showing the third left branchia covered by the branchiostegite. x289. 



Fig. 194. Part of sagittal section of eyestalk of a .slightly younger embryo. x289. 



Fig. 195. Partof transverse .section, showing branchia, of the third larvaof ^l/;>/teH.s «(Htteyt( twenty- 

 four hours old). x289. 



Fig. 190. Nearly median longitudinal .section of first larva of same. The anterior lobes of the 

 midgut (}«(/') still contain unabsorbed yolk. Compare PI. xxi, Fig. 1. x58. 



Fig. 197. Part of transver.se section, showing the papilla, which bears the median eye in the tir.st 

 larva of same, x 289. 



Fig. 198. Transverse section of first larva, cutting the lateral fiber balls of the brain, the anterior 

 lobes of the midgut, and the green gland. x289. 



Fig. 199. Part of transverse section through an advanced embryo of yl/p/iews s«Mfcyi, parasitized 

 by a fungus, most of the cells of which are encysted. From brown sponge, Abaco, 

 Bahama Islands, v. Appendix II. xl86. 



REFERENCE LETTERS. 



all., abdomen. 



Ah. VI, sixth abilnmiual appcndajje. 



acp., accessory pigment cells. 



ag., green glaud. 



ag. «., end sac (?) of gl.and. 



««. «., superior abdominal .aorta. 



l>g., branchiostegite. 



!>. s., B. S., l)l(>i>d space. 



br.^, branchia of third left aiiibiilatnry limb. 



CO., crystalline cone cells. 



eg., corueagen. 



oh, lens. 



CO., crystalline cone. 



ca., f«.'--, cysts of parasite. 



cs.'', smaller, naked cells of parasite. 



(/.*■-'", segmental ganglia. 



!//., Kber-mass of second antenna-. 



gma., anterior gastric muscle. 



M., heart. 



Hd., hypodermis. 



Ilg., hindgut. 



Lt., labrum. 



I.e., longitudinal commissure. 



mg., midgut. 



mg.', anterior loltes of midgut. 



mg.', lateral lobes of midgut. 



mg.', posterior lobes of midgut. 



mo., mouth. 



ma., masticatory stomach. 



mu, e., extensor muscles of .abdonum. 



mu.f., flexor muscles of .abdomen. 



«. c, neural cord. 



oc, ocellus. 



oe., wsophagus. 



0. G., o.g., optic ganglion. 



of., optic enlargement of brain. 



op., ophthalmic artery. 



pa., i)ericardial sinus. 



pr., perineurium. 



S., rostrum. 



Set., retina. 



rtl., nucleus of proximal retimilar cell. 



sag., brain. 



S})., par.asitic growth. 



St. «., stern.al blood sinus. 



T.. telsou. 



y., yolk. 



