CRUSTACEA. 5 



abruptly deflected for nearly an inch at the margins, and wry indistinctly 

 trilobate. 



Axis very broad, width more than two-thirds the width of the body. Seg- 

 ments broad and flattened, abruptly deflected at the anterior and posterior 

 margins and separated by very narrow transverse furrows, which are scarcely 

 distinguishable for their entire length, but arc mosl noticeable at the margins 

 of the axis, where lie the deep depressions to the leg-bases or visceral 

 supports. 



The deep transverse furrows along the middle of the segments are con- 

 spicuous and most distinct toward the lateral margins of the thorax and upon 

 the broad beveled articulating planes. The same liability to error in regard 

 to the anterior and posterior limits of the segments is noticeable in the lower 

 surface of this species as mentioned in the description of Homalonotus 

 Dekayi. The segments are evenly curved over the axis and posteriorly 

 deflected toward the margins. 



Ptgidium elongate-sub-triangular. Surface depressed-convex, sloping evenly to 

 the margins. 



Axis well defined and composed of ten annulations, the articulating ring 

 being the posterior half of the apparent last thoracic segment. These annu- 

 lations are broad, flat or slightly rounded, and arc nearly transverse, with a 

 slight forward bend over the axis. 



The pleura bear seven or eight distinct annulations. Posterior margin 

 slightly produced. In one specimen the posterior extremity is broken away, 

 its extension being indicated by the slope of the lateral margins, and in the 

 other it has been displaced and forced to one side. 



Surface of the test characterized by tubules of comparatively small size, 

 which have left their impressions on the cast of the lower surface. 



Observations. Of this remarkable species of Homalonotus hut two examples 

 have been discovered. The smaller of these, and somewhat better preserved 

 specimen, showing the pygidium ami five thoracic segment-, has served as 

 the type of the original description, and the other which is here figured 



