REPORT OF DIRECTOR AND STATE GEOLOGIST 1900 r2l3 



Porcellio spinicornis Say 



This species seems to prefer the crevices of rocks, specially 

 shady limestone ledges. Also, along with the preceding it 

 occurs under flat stones and boards, in the vicinity of dwellings. 



Porcellio scaber Latreille 



This is a widely distributed species but in this locality it is 

 uncommon except as living in a partially domesticated state in 

 greenhouses. Here they are abundant and attain their maxi- 

 mum size. This species is very variable as to color. 



Cylisticus convexus De Geer 



This species has resisted domesticating influences, being found 

 in the woods under logs and occasionally along roadsides, etc. 

 under stones. It is able to roll its body into a ball, resembling 

 in this respect the members of the genus Armadillidium. 



Metopnorthus pruinosus Budde-Lund 

 This species is common in greenhouses, about dwellings and 

 along country walls. 



Oniscus asellus Linnaeus 



This species is rare in this locality except in greenhouses. It 

 is the largest of the common species. It is distinguished from 

 the genera above mentioned by the fact that the organs of 

 respiration, adapted for breathing air, are not in the form of 

 tracheae, but are diffuse air chambers, lying in the outer por- 

 tions of the external branches of the five pairs of abdominal 

 appendages. In the genus Ligidium, however, there are no air- 

 containing organs of any kind. 



The paper published in the American naturalist, referred to 

 above, gives the literature of this group. 



