166 FRANK E. BEDDARD. 



which has occupied an unusual amount of space ; this worm; 

 however, possesses a more interesting exterior than is gene- 

 rally the case. 



Internal Anatomy. 



It appears from Mr. Benham's account of the internal seg- 

 mentation of Diacha3ta that there is some difference between 

 his species and mine in the segments occupied by the various 

 organs. There are six strong intersegmental septa (fig. 9), the 

 first bounding the vith segment 'posteriorly, and the last inter- 

 vening between the xith and xiith segments ; the position of 

 these is the same as in D. Thomasii, but there is one more. 



The spermatheca are situated a segment further back, 

 the first (of the three pairs) being in Segment vii, behind 

 instead of in front of the first thickened intersegmental 

 septum. Benham mentions the presence of a single pair of 

 long ''tongue-shaped" sperm-sacs attached to the anterior 

 wall of Segment xii. I find two pairs of sperm-sacs, both 

 small, and confined to the xith and xiith segments respec- 

 tively. The vas deferens funnels are in Segments x, xi ; 

 only one pair of these organs are mentioned by Benham, 

 those occupying the xith segment. The testes are in the 

 same segments, and occupy the usual position, i.e. they are 

 attached to the front of the segment opposite to the funnels 

 of the vasa deferentia. 



§ Integument. 



There are two points in the structure of the body wall which 

 require notice. The first point is the absence of those peculiar 

 structures in the epidermis which have been regarded as 

 possibly abortive setse; it is important to mention their 

 absence in Diachseta, for the reason that they are present in 

 Urochseta, which is in many other respects so closely allied to 

 Diachaeta. 



In all the segments of the body, commencing with the vith 

 (the first setigerous segment), the circular muscular layer is 



