40 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



the glands of the pereiopods and spun as it were into the 

 characteristic fabric. As the secretion emerges from the open- 

 ing at the tips of the pereiopods it hardens immediately as in 

 the spider's web. Bits of algse and grains of sand are frequently 

 woven into the tube which is thus rendered more inconspicuous. 

 Smith has observed that in Microdeutopus bits of fecal matter 

 are also worked into the web, but Holmes finds that Amphithoe 

 does not use excrement to increase the tube but passes it out of 

 the nest ; accumulations of it usually being seen at both ends of 

 the tube. 



The tubes are usually open at both ends and of uniform 

 diameter throughout. Their length is as a rule considerably 

 greater than that of the animaj. 



In constructing a tube, the first two pairs of pereiopods are 

 seen to be in rather rapid motion, passing back and forth over 

 the space which the tube is to occupy. By rolling over and con- 

 tinuing this motion the tubular form is attained. 



Amphithoe and various other species frequently leave their 

 nests ; they seem, however, to show no particular preference to 

 return to those of their own making, but slip into any one that is 

 unoccupied or proceed to build another, which is done in a re- 

 markably short time, often in less than half an hour. Unciola 

 usually inhabits a tube, but has no spinning glands in its pereio- 

 pods and has never been observed to weave a web for itself. 



The tube-dwelling forms habitually remain in their tubes 

 with only the head and antennae thrust out. When disturbed 

 Amphithoe retreats further into its tube and seeks safety in flight 

 only when the intruding object is so persistent as to prevent 

 further retreat into the depths of the tube. Holmes has observed 

 Amphithoe dart out for food without letting go of its tube and 

 quickly retract itself with the food in its gnathopods and devour 

 it at leisure within its tube. 



The instinct to build tubes develops very early in life. A few 

 days after leaving the brood-pouch, the young set about construct- 

 ing nests like the adults, and exhibit precisely the same reactions 

 to stimuli and habits. 



BREEDING HABITS. 

 The eggs are discharged from the openings of the oviducts, 

 those from each orifice, according to Delia Valle, becoming 



