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Transactions . 



the exit of the duct to the exterior, the epithelium again becomes low, and 

 the cells have lost the glandular character. It is in this moiety that the 

 spermatozoa are found ; it corresponds to the diverticula, which in most 

 species of Fredericia form prominent outgrowths round the exit of the 

 duct ; but in this species, as in a few others, this " storage-chamber " does 



Fig. 5. — F. bollonsi. A spermatheca, drawn from a cleared specimen, a, duct ; 

 b, sperm-reservoir ; c, furrow ; d, ampulla ; e, opening into the oesophagus ; 

 /, opening to the exterior. 



Fig. <i. — F. bollonsi. Longitudinal section through the spermatheca, but not in its 

 median plane, a, duct; b, sperm-reservoir; c, " diaphragm-cells " ; d, am- 

 pulla; e, -the dotted lines indicate the position of the oesophageal com- 

 munication, which is present in the neighbouring sections ; /, circular muscles 

 of duct. The position of the nuclei in the cells is diagrammatic. 



not project beyond the outline of the ampulla. As seen in transverse section 

 it is single, it is not a double rudiment ; it surrounds the ampulla con- 

 tinuously, and in the entire specimen it can be seen, too, to be separated 

 from the ampulla by only a slight constriction, which I dfd not observe 

 in the sections. 



The duct of the spermatheca takes its origin at the apex of a conical 

 group of cells which project far into the cavity of the ampulla ; hence in 

 longitudinal sections the cavity is divided into three chambers — a pair of 

 smaller and one median larger, the vi pair " being really continuous round 

 the circumference. 



The duct, after leaving the ampulla, remains as a narrow tube, which 

 passes obliquely downwards and forwards to its pore at the anterior end 

 of segment v ; here it opens directly to the exterior without any glandular 

 annexe. The wall of the duct consists of an epithelium surrounded by a 

 coat of muscle. The duct is about twice the length of the ampulla. 



Remarks. — So far as my acquaintance with the literature enables me 

 to compare this worm with those previously described, it must be regarded 

 as new, for amongst those species of the genus in which the spermatheca 

 is without diverticula, as enumerated by Michaelsen (10), Eisen (7), 

 Bretscher (6), and others, I find none that agrees in all points with the 

 present one. 



From a superficial examination it seemed likely that it would fall into 

 the species F. bisetosa Levinsen, with which it agrees in the limited number 

 of chaetae per bundle, and in one or two other features ; but, as Michaelsen 

 states that the spermathecae are provided with " zwei siclt gegenuberstehenden, 

 kugeligen frei abstehenden DivertiJceln," it is impossible to bring it within 

 that species ; moreover, it disagrees on other grounds. 



All the species hitherto described in which the diverticula are absent 

 differ from the present in one or more other characters, such as the number 

 of chaetae in the bundle, the presence of glands at the external opening 



