ANALYSIS OF THE LESSONS. XXIX 



LESSON XC. THE EYE IN THE ANNELLATA, CRUSTACEA, MYRIAPODS, 



AND INSECTS, p. 289. 



1297. Eyes always found in the Annellata. 1298. The number of them hi 

 the medicinal Leech. 1299. In the higher forms of worms reduced to two. 

 1300. In the higher forms of CRUSTACEA the eyes are pedunculated. 1301. Plan 

 of their construction. 1302. The eyes of the MYRIAPODS described. 1303. The 

 eyes of INSECTS. 1304. The compound eye. 1305. Eyes for short vision. 

 1306. Eyes adapted for longer vision. 1307. Bees have Telescopic vision. 

 1308. Description of it. 1309. Disagreement of authors in regard to the struc- 

 ture of the eye in Insects. 1310. Structure according to Straus-Durckheim. 

 1311. The opinions of Marcel de Serres. 1312. Miiller's opinions. 1313. He 

 discovered a crystalline lens. 1314. The conical lenses according to Straus and 

 Miiller. 1315. Demonstration. of these views. 



LESSON XCL THE EYE IN INSECTS, CONTINUED, p. 291. 



1316. The subject not exhausted by Miiller. 1317. Another account. 1318. 

 The conical bodies. 1319. Their color. 1320. They are supposed to represent 

 the vitreous humor. 1321. Their figure. 1322. Disposition of the optic fila- 

 ments. 1323. The filaments possess an axis-cylinder. 1324. The cones in a 

 Caterpillar. 1325. The method of connecting the eyes with the brain demon- 

 strated. 1326. The inferior portion of the brain in Blatta Americana. 1327. 

 The fatty layer in Musca carnaria. 1328. The action of this form of eye. 1329. 

 Necessity for this form of visual organ. 1330. Enumeration of the facetted 

 eye. 1331. The hairs, or eye-lashes. 1332. Bees possess them: for why. 

 1333. The Telescopic eye. 1334. Its structure described. 



LESSON XCIL THE EYE IN INSECTS, CONCLUDED, p. 295. 



1335. The connection of the optic nerves of the single eyes demonstrated. 

 1336. Structure of the transparent cornea. 1337. Method of connection with 

 the lenses. 1338. Probability of an aqueous humor. 1339. Mechanical figure 

 of the facetted eye : the reason for it. 1340. The variation in shape of them. 

 1341. Demonstration. 1342. Structure of the cornea in Prionus longimanus. 

 1343. The membrane lining the cornea. 1344. Description of it. 1345. The 

 cornea after removing the membrane. 1346. Description of it. 1347. The 

 prismatic, or lenticular bodies. 1348. There are double-convex lenses in addi- 

 tion. 1349. The great substance of the cornea. 1350. Straus and Muller agree 

 in the depth of the cornea. 1351. Wherein they differ. 1352. Resume". 1353. 

 Concluding demonstration. 



LESSON XCIII. THE EYE IN ARACHNIDA, MOLLUSCA, AND FISHES, . . p. 299. 

 1354. The largest eyes in this class are met with in the Scorpions. 1355. Their 

 structure described. 1356. No visual organs in the slow-moving Mollusca. 

 1357. The eyes in the Gasteropods. 1358. They are placed on tubercles. 1369. 

 Demonstration of Cyprea tigris. 1360. The like in Carinaria Mediterranea. 

 1361. The eyes of Mollusca approximate Fishes. 1362. The number of eyes in 

 the Vertebrata. 1363. The eyes of Fishes. 1364. Their crystalline lens. 1365. 

 The Fishes in which the visual organs are of least size. 



