618 



INDEX 



Leptcena, 231, 245, 284, 395. 



absence of punctaj in deltidium of, 

 260. 

 of straight hinge-line in young, 



268. 



dorsal fissure in, 263. 

 pedicle-opening in, 241. 

 rhomboidalis, 315. 



and Strophonella striata, paral- 

 lel development in, 333. 

 aperture of ventral valve in, 



394. 



chilidium in, 264. 

 development of, 325. 

 discussion of, 322. 

 geniculated curtain in, 397. 

 hinge in, 333. 

 neanic, 258, 

 nepionic stage in, 268. 

 striaa in, 397. 



spiniform processes in, 78. 

 spiral impressions on valves of, 



276. 



Leptcenisca, 245, 256. 

 Leptobolus, 243, 394. 

 Leptocoelia, 245. 



Leptodora, first pair of appendages of, 

 191. 

 trunk segments and appendages of, 



191. 



Leptoplastus, 142, 145. 

 Lernceascus nematoxys, suppression of 



limbs in, 83, 85. 

 lianes, 87. 



Lichadidae, 129, 131, 139, 157. 

 defined, 150. 

 differentiation and specialization in, 



151. 



lobes in glabella in, 148, 149. 

 Lichas, 129, 150, 157. 

 glabella in, 135, 150. 

 pygidium in, 149. 

 scabra, spiniform processes in, 78, 



79. 

 Lima, development of spines in, 14. 



squamosus, spines in, 51. 

 Limnaida, first pair of appendages of, 



191. 



limnloids, aquatic, suppression of ap- 

 pendages in, 83. 



classed with arachnids, 109. 

 tail spine in, 84. 



Limulus, 109, 225. 



appendages in embryo of, Packard, 

 209. 



development of anterior legs in, 84. 



free-cheeks in, 118. 



optic nerve in, 223. 



polyphemus, spines in, 22. 

 telson spine in, 84, 85. 



tail spine in, 84. 

 Lindstrcemella, 244. 

 Lingula, 231, 238, 243, 255, 284, 387, 394. 



adult brachia in, 282. 



arms of, 276. 



complanata, holoperipheral mode of 

 growth in, 266. 



development of, Brooks, 256. 



difference in valves in, 234. 



elongate form of shell in, 287. 



gibbosa. 315. 



inception of, Hall and Clarke, 286. 



ontogenetic stages of, 286. 



outline and hinge in, 238. 



pedicle in, 235. 



-opening in, 241. 



protegulum in, 234. 



pyramidata, development of, 388. 



riciniformis, holoperipheral mode of 

 growth in, 266. 



tentacles in, 275. 



of taxolophus in, 277. 

 Lingulae, fossil, casts of pedicles of, 



Davidson, Walcott, 257. 

 Lingulasma, 243. 

 Lingulella, 387. 



Lingulidae, Obolella, stage in, 267. 

 Lingulops, 231, 243. 

 Linnarssonia, 231, 244. 



protegulum in, 234. 

 Liostracus, 142, 145, 172, 179. 



cephalon in protaspis forms of, 182. 



early protaspis stage in, 123. 



eye-line in, 125, 179. 



eyes in, 126, 180. 



glabella of larval stages of, 141. 



onangondianus, 171. 

 Liothyrina, 231, 246, 247, 291, 307. 



calcareous loop in, 281. 



dorsal pedicle muscles in larva of, 

 251. 



fleshy portion of arms in, Han- 

 cock, 292. 



loop in, 292. 



