1914.] NATURAL SCIENCES OF PHILADELPHIA. 49 



extend at a slight angle and not parallel to the body. This row is, 

 furthermore, not continuous, but generally interrupted in the middle 

 for a short distance on either side of the median line. Occasionally, 

 however, I have noted specimens in which this row of spinules is 

 practically continuous, though there is always a slight break. The 

 length of the entire cephalothorax to that of the abdomen is as 7 : 5. 

 The first abdominal segment is very slightly smaller than the 

 fifth thoracic segment, and the whole abdomen tapers but little. 

 HoAV small this taper is may be readily seen from the following pro- 

 portional width of each segment at its posterior l^order. 



First segment 27 



Second segment 26 



Third segment 24 



Fourth segment 21 



The proportional lengths of the four abdominal segments beginning 

 with first are 11 :7 :6 : 2. All the segments are cylindrical. The 

 posterior borders of the first, second, and third segments are minutelj" 

 serrated (PI. IV, fig. 2). The last abdominal segment is less than one- 

 fifth as long as the first segment and bears on its posterior border a 

 fringe of unusually long and heavy spines (PI. IV, fig. 2). 



The stylets are short (PI. IV, fig. 2). Their length and width are 

 to each other as 4 : 3 — a proportion that shows them to be very wide. 

 Below the point of insertion of the short lateral spine, which may or 

 may not be plumose, the stylets taper rapidly. In addition to this 

 lateral spine, there is a row of slightly shorter spinules (usually from- 

 four to six), extending from the lateral spine, ventrally, slightly below 

 the middle of the side of each stylet. Forbes mentions "a row of 

 long spinules on the ventral side of each ramus, extending from the 

 middle line of the anterior border to the point of insertion of the 

 lateral spine." I have never noted such a row of spinules in any of 

 my specimens, though this entire minutely spinose armament of the 

 stylets must be considered a variable feature. , There are two or 

 three rows of minute hairs extending obliquely from the middle of 

 the anterior border of each stylet towards the posterior border. 

 The interior border of the stylets is often .plumose (Schmeil found 

 an "unbehaarten Innenrande") and the inner and posterior dorsal 

 surfaces are armed with irregular groups and rows of short, blunt 

 spines (PI. IV, fig. 2). Forbes and Schmeil both note that the 

 outermost apical bristle "is placed high up on the side of the stylet./' 

 In his fig. 1 on pi. VIII, Schmeil has shown this to be the case, but 

 in fig. 2 of the same plate he shows this spine inserted directly beside 

 4 



