OF CONCHOLOGY. 215 



near the coast are more than twice the size of those of drier 

 and cooler localities. 



While on this species its entire range may as well be discussed. 

 The type came from near San Diego, and Mr. Gabb did not find 

 it on the peninsula south of that point. It is the prevailing 

 species of the wrinkled group throughout the Sierra Nevada, as 

 far north as Nevada County, where Mr. Voy found specimens so 

 dwarfed and smooth as scarcely to be recognizable, except by 

 the disproportionately large body-whorl, though the normal 

 number of whorls (5J) continues. I found them large and fine 

 along White River, Kern County, and smaller at Copperopolis, 

 Calaveras County, where they have the umbilicus much more 

 open than further southward. Thus it has a range in the Sierra 

 Nevada of about 450 miles, nearly north and south, and always 

 presents unmistakeable characters, although subject to much 

 variation. None are found near the coast north of San Pedro, 

 where they occur sub fossil and very rarely living. They are 

 abundant in some can6ns of the mountain ranges immediately 

 north of Los Angeles. 



Those reported from localities in or west of the coast range 

 northward, were probably other allied species,* although they 

 may jiave been found at Benicia, washed down by the rivers 

 which converge there. In my Washington Territory report 

 (Pacific R. R. Rep., xii. ii, 185U), this species is mentioned as 

 from Fort Vancouver, W. T., on the Columbia river. The speci- 

 mens were so named by Dr. Gould, but it is not unlikely that 

 they were collected in California and accidentally mixed with 

 northern ones. 



Being the only one of the malleated group found in the Sierra 

 Nevada, and the widest in range of any of them, it is a good 

 species to study the variations of form and surface upon. The 

 result of comparisons show that these do not vary so much in 

 size and umbilicus, while the number of whorls is constant. 

 Extending from latitude 33° to 39°, its point of highest devel- 

 opment, both in size and numbers, is about latitude 35°, and it 

 evidently becomes dwarfed near its northern limits from the in- 

 fluence of cold, as moisture is more abundant than southward. 

 It is therefore quite improbable that it should occur at the 

 Columbia River, more than ten degrees of latitude farther north, 

 and none of the numerous collectors in the intermediate region 

 have found it. 



The H. NicTcliniana, sent to Dr. Lea by Dr. Trask as from 

 "Deadman's Island," which is a mere rock in San Pedro Bay, 

 if really from there was probably a poor specimen of tudiculata, 

 which might be confounded with that if imperfect (See " Ob- 

 servations," &c, vol. xi. p. 111.) 



