THE MUSEUM. 



141 



A group of Cyclostomas, C. cltuuii- 

 *(ins, C. assiinile, C. tcncbrosuut, and 

 perhaps others, spins a thread by 

 whicli they hang from the lower side 

 of projecting rocks. When the weath- 

 er clears after a rain, numbers may be 

 found thus at rest, particularh' in the 

 early summer, when the young abound. 

 Whether they can haul in their lin I 

 am unable te say, but guess they can- 

 not; for many arc found with the bor- 

 der broken, which could hardly be so 

 common, unless caused bj- a fall from 

 some height. If in this position they 

 fall, it must some times be a distance 

 of fifty, or it may be hundreds of feet. 

 These are all delicate shells; and the 

 power of suspension seems as if de- 

 signed for their injury or destruction. 

 • Helix stiginatica, and its allies live 

 under stones or among dead leaves. 

 They are dull in color, and the most 

 of them small in sijre. //. stigviatica 

 is never found fairly in the daylight. 

 Once only, if I rightly remember, I 

 found an individual which had just 

 turned the corner of the rock under 

 which it lived. Why do thej* not 

 come out to the light, and what do 

 they live upon in the dark retreats. 

 Another group of similar habits com- 

 prises tlclix Titanica. H. piilc/icriiiia 

 and others. These have longitudinal 

 lines of bristles or rather stiff hairs, 

 which arc quite conspicuous in the 

 young shell, but diminish, wear away, 

 or quite disapper with age. 



Shells often cease growing for a 

 time, so far at least as relates to their 

 calcarous covering. Their growth is 

 interrupted during the dry season, and 

 it may also be an unusually dry time 

 in summer. In banded shells, where 

 the growth is resumed, the pattern of 

 their markings is often, perhaps always 

 changed. The bands may be moved 

 to the right or left, or be divided into 

 two, or two may be united, or a color 

 may be suppressed, or a new one in- 

 troduced, or any one color may be 

 widened or narrowed. In //ilix 

 picla the variety of markings is almost 

 innumerable. Whlie the animal re- 



mained ijuiescent as a whole, why did 

 not the several parts retain their rela- 

 tive positions.' The color-secreting 

 glands must have changed in position. 



The wide diffusion of some species, 

 and the e.xtremely limited area in 

 which others are found, e.xcite in the 

 inquiring mind a desire to know the 

 causes of this unecjual distribution. 

 /fclicina ngiiia, in several forms is 

 found in the whole of the mountain 

 range of the western part of the island. 

 11 die ilia adspcrsa is another exten- 

 sively diffused species besides being 

 very variable in size and markings. 

 On the other hand, Crclostotiia fovea- 

 tiiiii has been found in only one lo- 

 cality, at the base of a high projecting 

 cliff, in considerable numbers, but all 

 dead; nor is it known where it lives. I 

 have looked upwards from below, and 

 have climbed to the top and looked 

 downwards in vain. Not more than 

 two or three have been obtained in a 

 moribund state, a single one only with 

 sufficient life to enable Gundlach to 

 describe and figure the animal. A few 

 square yards contain all we know of 

 this species. Lignus fasciata is found 

 from one end of the island to the 

 other, and at all elevations above the 

 sea, under several forms which have 

 been described as distinct species. 

 Helix pieta is another widely dif- 

 fused shell, and e.xtremely varia- 

 ble in color and si;?e. I have ob- 

 served many young in the top 

 branches of a high tree just felled, on 

 the very top of the mountains, in 

 Yateran. It seems to be a high climb- 

 er, which may account for its com- 

 parative rarety, fully grown and alive. 

 I have met with very few. 



Cylindrella is largely represented in 

 Cuba, more than eighty species being 

 enumerated in the later catalogues. 

 Most of the species are extremely local, 

 several, so far as known, being re- 

 stricted to localities of a few yards 

 square, or to a few rods. Doubtless 

 other localities will be discovered for 

 many of them. A few as C. Poeyeiia, 

 C. eleguiis, C. irrorata, are much 



