326 W. A. HASWELL 
ten narrow cylindrical bodies of varying length surrounding 
the pharynx, with which they run parallel, ending blindly 
behind, and in front terminating in the pharyngeal papillae. 
They are solid bodies each of the nature essentially of a group 
of greatly elongated cells, the anterior end of each of which is 
produced into a narrow duct terminating in a very minute 
aperture on the surface of the corresponding papilla. 
In Odontosyllis the arrangement of these glands is, as 
pointed out by Malaquin, somewhat modified by their restric- 
tion to the ventral side. In Amblyosyllis and in certain 
species of Autolytus, as also observed by Malaquin, they 
are fused together into a pair of irregular masses of considerable 
size. ‘hese divide up in front into narrow lobes running for- 
wards to the papillae. 
IV. THe PRovENTRICULUS: GENERAL STRUCTURE. 
‘The proventriculus is an exceedingly conspicuous and very 
characteristic structure to which reference is made by all 
writers who have dealt with this group of the Polychaeta. 
But it was not till, in 1881, Kisig published his paper entitled 
‘Ueber das Vorkommen eines schwimmblasenihnlichen Organs 
bei Anneliden” that an approximately correct interpretation 
was given of the structure of this complex organ. 
In Kisig’s account, though it marks a distinct advance in 
our knowledge, there are certain omissions and certain mis- 
statements. Of the former one of the most important is the 
failure to recognize that the muscular tissue of the radial 
columns, which make up the bulk of the substance of the wall 
of the organ, is of the striated type. The true nature of this 
tissue was pointed out by the present writer in a short paper 
published in this journal in 1886; and the subject, as regards 
the histology of the muscular tissue, was further developed 
in 1889 (6). 
In 1893 was published Malaquin’s * Recherches sur les 
Syllidiens *. In this comprehensive work the author gives 
a very full account of the proventriculus, summarizing pre- 
viously published results and adding numerous observations 
