CAPRELLID®. 35 
Fam. I].—CAPRELLIDZ. 
PEREION cylindrical. Pleon rudimentary. Appendages 
attached to the cephalon normal and well-developed. 
Pereiopoda having the first joints, or coxz, fused with 
the segments of the pereion to which they are respectively 
attached. Branchiz attached to the third and fourth 
segments of the pereion. Pleopoda rudimentary or 
obsolete. 
It is to the species belonging to the several genera in 
this aberrant family that the popular name of spectre or 
skeleton shrimp has been applied, the idea being sug- 
gested by their thin and skeleton appearance, as they 
crawl among the weeds under water. 
The slender elongated form of these animals well con- 
trasts with the short and dilated bodies of those com- 
posing the following family Cyamide. These animals 
also are free and roving in their habits, whilst the Cyami 
are parasitic upon the Cetacea, and evidently, from their 
structure, sluggish in their movements. 
The Caprellidz have recently been divided by Kroyer 
into several genera beyond those adopted in the following 
pages, founded, for the most part, on the relative structure 
of the minute terminal portion of the body, and the 
greater or less development of its rudimental segments 
and appendages. These characters appear, however, to 
us of too slight importance to warrant such a step, the 
more so since they only exist in an abnormal condition. 
