570 MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 



PLATE LIV. 



FIG. L'OII. Ommatidium of eye of .small adult Alpheu* xtmlcyi (from brown sponge) ; pigment removed 



by nitric acid. x294. 

 FIGS. 201-U04. Transverse sections through four adjacent ommatidia of first larva of same. In Fig. 



201 the corueagen is cat, and in Fig. 202 the nuclei of the coue mother cells. In Fig. 



204 the rhabdom is sectioned and the seven proximal retiuular cells. x2!>4. 

 FIGS. '_>o.">-208. Transverse sections through adjacent ommatidia of the adult eye, taken at various 



levels. Fig. 205, the deepest section, shows the peculiar seven pronged figure of the 



rhabdom. The proximal retinular cells appear in sections, as it' fused together, x 294. 

 FIGS. 209-211. Transverse serial sections through the first larva of Alpheus saulvi/i. -x 74. 



KEKKKK-NCK LKTl'EES. 



A. I, first antenna. 



A. II, second auteuua. 



a. op., accessory pigment, cell. 



uc.pn., nucleus ot .iiTi's.Movy jii^ini'iit cell. 



ao., car. 



lint., intiTccptiiif; or liaNcinciil ninniliniiif . 



cc., crystalline' c.nnii CC.HH. 



'i-, '-onica-icii. 



c7., Icllh. 



Co., no., crystalline- cone. 



i-nili., cone membrane. 



ltd., hypodermis. 



me., membrane of distal retiuular cells. 



/., nerve fibers. 



oc. , ocellus. 



017., optic ganglion. 



a!'., optic enlargement of brain. 



pap., papilla of ocellus. 



p.tj. <., distal retinular cells. 



/;., rostrum. 



Rb., >'li., rhabdom. 



Set., retina. 



rtl. , proximal retiuular cells. 



