"228 SABBLLA PENICILLUS. 



considerably advanced, the long filamentous processes projecting from the tips give a 

 novel character to the organs. 



Anteriorly the buccal segment lies in a hollow between the two pillars of the dorsal 

 fan, a more or less separate fan-shaped lamella, tinted of a deep reddish brown, occurring 

 on each side. From this the marginal collar passes ventrally to expand into the prominent 

 and generally reflexed lamella on each side of the median fissure, where it is distinctly 

 thickened. A band on each side of the median oral process joins it to the fold a little 

 higher. The first shield on the ventral surface behind the collar is continuous from side 

 to side, and is the largest of the series of glandular scutes, though it is opposite the 

 first bristle-bundle the latter would seem to pertain to the segment behind it. 



The mouth leads into a simple alimentary canal, which, when seen from the dorsum, 

 forms a moniliform tract from end to end — wider anteriorly and narrower posteriorly. 

 The septum in each segment retains it firmly in position. The contents can be seen 

 through the transparent walls of the canal, and in one consisted of pale granules 

 anteriorly and posteriorly of muddy sand. At each side of the gut anteriorly is a long 

 granular sac (segmental organ). 



The body shows little or no narrowing anteriorly, remains of similar diameter for a 

 considerable distance, then in preservation may increase in breadth behind the anterior 

 third, and thereafter gradually tapers to the tail, ending in the anus, which is often 

 bilobed. In lateral view r the margin of the vent slopes from above downward and 

 backward, the ventral edge thus projecting considerably. Seen from above the aperture 

 is bifid inferiorly, and a triangular area is differentiated on the dorsum in front of the 

 aperture. Both dorsal and ventral surfaces are plano-convex, thus in transverse section 

 being more or less elliptical, the dorsal, however, being generally more smoothly 

 rounded, with a pale streak in the middle line from the dorsal vessel. The ventral 

 surface has a continuous series of scutes from one end to the other, and with the 

 exception of the first all are divided by the median groove — giving a right and a left 

 scute to every segment. The number of segments varies from 200 — 270 or more. 



The first region of the body (the so-called thoracic region) is distinguished by the 

 direction of the bristle-tufts, which slope upward and backward, and by the presence of 

 ventral rows of hooks. The setigerous processes vary from seven pairs to eleven, one 

 side occasionally having nine or ten and the other eleven. The first setigerous process 

 arises immediately behind the dorsolateral lamella, and is smaller than those following ; 

 moreover, it has no row of hooks dorsally. The bristles (Plate CXXVIT, fig. 6 d) are 

 arranged in a rather dense group and show a longer and a shorter series. The longer 

 forms (Plate CXXVII, fig. 6) have cylindrical striated shafts slightly narrowed toward 

 the origin of the wings which are narrow, the bristle thereafter ending in a translucent 

 and somewhat strong though flexible tip. No serrations on the edges of the wings have 

 been seen in these though striae go to the edge. The bulk of the group of bristles is 

 made up of those with shorter shafts and broader wings (Plate CXXVII, fig. 6 a), the 

 whole tip being rather broad until near its extremity, where it is abruptly tapered 

 to a fine point. In the cluster of bristles in the tuft various stages occur in the 

 developing bristles, some resembling a long, narrow knife-blade, others a deep-bellied 

 shorter blade. 



