EDRIOPHTHA LMIA . 



75 



the dead tests of Doliolum (one of the ascidians), in wliich they dwell much after 

 the fashion of hermit crabs, while Beroe, one of the jelly-fishes, furnishes a habi- 

 tation for others. 



The family Chelueid.e contains but a single species, Chelura terehrans, which 

 has several of the abdominal segments united, while the last three abdominal feet are 



Fig. 101. — Cystosoma nejjtmii, slightly reduced. 



greatly modified from the usual type. This species is, next to Z,im7ioria, the most 

 destructive of all Crustacea. The animal only reaches a length of about a third of an 

 inch, but its immense numbers make up for the diminutive size. Like Limnoria they 

 excavate burrows in the hulls of ships, the piles of wharves and bridges, ,ind any other 

 submerged timber. It is in Europe that this species has caused the greatest damage ; 

 it is almost unknown in this country, as it 

 has only been seen in our waters in a few 

 isolated cases. 



The CoEOPHiD^ is a much larger fam- 

 ily, represented in our waters by many 

 species. The forms are largely dwellers in 

 tubes, which they either form for them- 

 selves or find in the deserted homes of 



. T\/r„ s 4.1 • Fig. 102. — Cerapus ruhriconih, femsX^: below the 



marine worms, etc. Many of the species pincer of the male, enlarged! 



