QUESTIONS. 359 



249. Condition of the heart and breathing-organs ? 



250. What divisions of the Gasteropoda may be founded on the nature of 

 the breathing-organs ? 



251. Condition of the young water-breathing Gasteropod ? 



252. Structure and modifications of the shell in Gasteropods ? 



253. What are the two leading conditions of the mouth of the shell ? 



254. General characters of the Nudibranchiata ? 



255. Nature of the foot in the Heteropoda ? 



256. General characters of the air-breathing Gasteropods ? 



257. General characters of the Ptcropoda? 



258. General characters of the Cephalopoda? 



259. Nature of the "arms" and their suckers in the Cuttle-fishes? 



260. Structure of the " funnel ? " 



261. Nature of the ink-bag ? What living Cephalopod is without an ink- 

 bag? 



262. Nature of the breathing-organs ? Of the circulatory organs ? Of 

 the respiratory process ? Of the nervous system ? 



263. Peculiarities in the reproductive process in the Cuttle-fishes ? 



264. Nature of the internal shell of the Cuttle-fishes ? 



265. What two living Cephalopods possess an external shell, and ^vilat 

 are the differences between these ? 



266. Characters of the Dibranchiate Cephalopods ? Give examples. 



267. Describe the shell of the Argonaut ? 



268. Characters of the Tetrabranchiate Cephalopods ? 



269. Describe the shell of the Pearly Nautilus ? 



270. Mention some fossil forms allied to the Pearly Nautilus ? 



271. General characters of the Vertebrata? 



272. What is the " notochord ? " 



273. General structure of a " vertebra ? " 



274. Kegions generally recognizable in the vertebral column ? 



275. General structure of the fore-limb ? 



276. General structure of the hind-limb ? 



277. General structure of the digestive system ? 



278. Source of the blood ? Nature of the " blood-corpuscles ? " 



279. What Vertebrate animal has no heart ? 



280. General nature of the respiratory organs ? 



281. What is the difference between a gill and a lung ? 



282. General structure of the nervous system ? 



283. Define the terms "oviparous," "viviparous," and " ovo- viviparous." 



284. Into what primary sections are the Vertebrata divided by Huxley ? 



285. What are the five classes of Vertebrates ? 



286. General characters of Fishes ? 



287. Chief forms of scales ? 



288. Nature of the " lateral line ? " 



289. Form of the vertebrae of a Fish ? 



290. Position and connections of the ribs ? 



291. Nature of the " interspinous bones ? " 



292. Nature and position of the limbs of Fishes ? 



293. Distinction between the " paired " and " median fins ? " 



294. Number and names of the median fins ? 



295. Difference between homocercal and heterocercal tail ? 



296. What are the "rays?" Difference between "soft rays" an<J 

 " spinous rays ? " 



297. What are the " pyloric cseca ? " 



