38o REPORT OF NEW JERSEY STATE MUSEUM. 



This tribe sometimes known as the Maioidea, including a 

 great number of forms, has been divided into two families, as, 

 now understood. 



Family MAIID^. 

 The Spider Crabs. 



Basal joint of antennas slender or well developed. Chelipeds 

 usually not much long"er or more massive than other legs. 

 Eyes retractile or not against sides of carapace or in orbits, 

 which latter distinctly or not defined, though frecjuently more or 

 less incomplete below% or marked with open fissures in their 

 upper and lower edges. 



Their bodies are usually narrow in front, sometimes orbicu- 

 lar. There is always a beak as that found in our common 

 "spider crab." As their bodies are also furnished with many 

 hairs, which may be either hooked or straight, and which vary 

 in arrangement and form in the different genera and species, 

 they collect quantities of dirt and mud. Their backs also often 

 become covered with various sedentary animals like tunicates, 

 sponges and bryozoans, also algse, and as these are often secured 

 by the hairs they grow in profusion, sometimes until their host 

 is scarcely recognizable. The object of all this has been suggested 

 to be to afiford concealment from enemies. 



Genera about ninety or more, though only two in our limits. 



Key to the genera. 



a. Orbits with large blunt cupped postocular process into which eye is 

 retractile, but not completely concealed. hyas. 



aa. Orbits complete, often tubular, completely concealing retractile eye. 



UBINIA 



Genus HYAS Leach. 



Hyas Leach, Edinburgh Encyclop., VII, 1S14. p. 394. Type Cancer areneus 

 Linnaeus, monotypic' 



Leach, 1. c, 1815, Am. Ed., VII. p. !?71. 



