The West American Scientist. 



Copyright, 1894, by W. J. Demorest. 



PILOCEKEUS SENILIS— CRISTATE SPECIMEN. 



ily replaced on grounds open to question. 

 The resurrection of the Linnsean name 

 Cactus offers a splendid opportunity 

 for a botanist to affix his name to a 

 multitude of valid species (and syn- 

 onyms!) not yet transferred — but pract- 

 ical botanists and horticulturists must 

 deplore such "botanical activity." 



The name Cactus was first used in a 

 restricted generic sense for a group of 

 Opuntiae by Lemaire, a fact which 

 would add further confusion if we were 

 to resurrect the name as proposed, or 

 as attempted. 



My views have already been partially 

 recorded on the nomenclature question 

 in Science, xvii, 67 (reprinted in this 

 magazine, vii, 206), but new points 

 continually arise where individual 

 judgment must be used. It seems ex- 

 tremely doubtful if ever Cactus will 

 replace Mammillaria in either tech- 

 nical or popular use; or that Fremont- 

 odendron can long replace Premontia, 

 or any name supplant our Washingtonia 

 as applied to our Californian fan palm. 



It may be sentiment, but sentiment 

 must always form a part of our language 

 and receive consideration, especially 

 when it aids language to perform its 

 duty. The only final settlement of these 

 vexing questions will be through com- 



mon usage and a law ignored by 

 horticulturists and the more conserva- 

 tive of our botanists will ultimately 

 disappear. G. B. Orcutt. 



MEXICAN SHELLS. 



While spending a few weeks in and 

 near Mexico City, in 1894, the following 

 land and fresh water shells were ob- 

 served. There was no opportunity for 

 more than very desultory work, so that 

 the list is necessarily short. 



SucciNEABREVlsDkr. I found quite 

 a colony of this little species in the 

 pine woods on the mountains between 

 the cities of Mexico and Puebla ; near 

 what is locally known as Rio Frio. 



S. UNDULATA Say. A common 

 species in the City of Mexico; my 

 specimens were collected near the Castle 

 of Chapultepec. 



Helix aspersa Mull. This intro- 

 duced European snail has become very 

 abundant along the ditches and canals 

 in the City of Mexico, and in gardens 

 has become quite a nuisance. 



H. Humboldtiana Val. A single 

 specimen was found near the top of 

 the mountain pass, in going to Puebla: 

 said to be one of the commoner species 

 in the State of Mexico. 



