124 Mr. F. E. Beddard on the 



in the fifteenth segment, its calibre being three or four times 

 that of the cesophagus. 



The dorsal blood-vessel is single. The cerebral ganglia 

 lie opposite to the furrow separating the first from the second 

 segment ; they may possibly have been pushed forwards 

 with the everted buccal cavity. 



There is only a single pair of spermatheca?, which in com- 

 pensation are very large ; they occupy nearly the whole of 

 the available space in segment ix., and indeed they materially 

 encroach upon the cavity of segment viii., of course pnsliing 

 the septum which divides the two segments in front of them. 

 Each spermatheca (fig. 10) consists of a large thin-walled sac 

 {sp) filled with hard coagulated yellowish matter ; this commu- 

 nicates with the exterior by a duct which is very thick-walled 

 and has a metallic yellow colour ; connected with the duct is 

 ancqually thick-walled, somewhat oval diverticulum ('./), which 

 becomes constricted just before joining the sj)ermathecal duct ; 

 at this point it is furnished with ttvo subsidiary diverticula ('/'); 

 each of these small diverticula is really double and consists of 

 two globular sacs (fig. 11, d!) opening by a common duct. 

 These minute sacs, less than a pin's head in size, are opaque 

 yellow and contain sperm. The spermathecal duct after it is 

 joined by the wide diverticulum becomes somewhat dilated and 

 opens on to the exterior just below tlic mesentery dividing its 

 segment from the eighth. So far as I could make out there 

 a]ipeared to be some slight variation in the number of the 

 small pouches belonging to the diverticula; but as the speci- 

 men is a unique one I am not in a position to give details 

 the recording of which would have necessitated the destruction 

 of the specimen. The sperm-sacs occupy segments x. and xi. ; 

 I am not quite certain whether they reach the twelfth seg- 

 ment. The atria have the lobate form so characteristic of 

 the Pericha^tida^, but they are nevertiieless rather unusual in 

 one point of structure : in all atria of this kind of which I am 

 acquainted with from figures or description or from myown dis- 

 sections the muscular duet which leads to the exterior comes off 

 from about the middle of the glandular mass, and is generally 

 conq)aratively short and curved into a horseshoe-shaped form ; 

 in Mc(jascolex cittgulatus the atria lie on either side of the 

 gut, to which they are closely attached ; more generally one 

 finds the atria adherent to the ventral parietes. They are 

 long and narrow, and extend from the eighteenth to the 

 twenty-fourth segment ; although long and 'narrow, they have 

 not the tubular form found in the atria of Acanthodrihis and 

 other genera ; they are composed of numerous lobules of 

 various sizes. The duct, however, comes olf from the ante- 



