OAPITBLLA CAPITATA. 



283 



The two genital segments, eighth and ninth (Fig. 132), have four bundles of strong spines 

 — a pair to each segment. Just in front of the ninth segment are two opaque bodies (glands), 

 one at each side. About the middle of the ninth segment and apparently immediately in 

 front of the papilla is the anterior series of ten spines — five on each side, the outer being 

 the smaller. They rapidly increase in size toward the middle line. The concavity of the 

 curve of each spine, like the point of the hook at the tip, is directed outward and backward, 

 the convexity looking toward the convexity of the adjoining series. A space occurs 

 between them and the posterior pair, the points of which are directed forward, and just 

 appear, under pressure, at the edge of the sexual aperture, which is ciliated. They are 

 four in number, but the two inner are much larger than the outer, and they are directed 



Fig. 132.— Modified, bristles of the eighth and ninth segments of Capitella capitata, Fabr. gb. Genital bristles. 



forward and inward, leaving a gap posteriorly between the pairs in which a pyriform 

 glandular copulatory organ with an irregular margin lies, the duct running foward to the 

 aperture. 



The digestive tract is segmented by the diaphragms, and the posterior end is ciliated 

 for some distance forward from the terminal anus. The corpusculated perivisceral fluid 

 moves to and fro by the side of the gut with considerable force. 



The anterior region (Plate XCVIII, fig. 20) following the peristomial segment 

 consists of seven segments, each nearly symmetrically divided by four rows of golden 

 bristles (Plate CVII, fig. 10). Each has two strong curves, and a double wing at the tip, as 

 well as a slight shoulder below the upper curve to which the wing is attached. The same 

 figure shows one of the tips, which are not very acutely pointed. In the line of the bristles 

 a sub-annulus often appears. 



In the ninth segment, hooks (Plate CVII, fig. 10 a) appear at the four points instead 

 of bristles. Two of the dorsal hooks are nearer each other than the other pair. 



