206 PROCEEDINGS OP THE ACADEMY OP [1883. 



are rather longer and larger tlian the others, and are rendered 

 conspicuous b}' a large vessel filled with bright green blood. 

 The tentacles are invested with ciliated epithelium, with actively 

 moving cilia, and in all respects bear a close resemblance to those 

 of the polj'zoa. In the allies of Manayunkia, they are regarded 

 as branchial appendages, and usually named cirri ; and although 

 this is unquestionably correct, as in the case of the corresponding 

 organs of the polyzoa, thej' perform a varied function, and may, 

 with equal correctness, be called tentacles. 



When Manayunkia is about to withdraw into its tube, the 

 lopliophores approach, and together with the tentacles form a 

 close longitudinal fascicle. Along the lophophores, at the base of 

 the tentacles, there is a row of half a dozen or more brownish pig- 

 ment spots, resembling eyes, but not having the usual constitution 

 of such organs. The segments of the body of Manayunkia, suc- 

 ceeding the head, are furnished on each side with a fascicle of 

 locomotive setfe, which is divided into two portions, one usually 

 consisting of shorter setse than the other. The fascicles, when 

 most protruded, project from a papilla, which disappears with the 

 partial retraction of the former. They are projected directly 

 outward or in a slanting manner either forward or backward, and 

 are moved in the same manner and by the same arrangement of 

 muscles as in other chsetopods. The number of podal setae is 

 from four to ten in each fascicle. In several mature individuals 

 the numbers in the different segments were as follows : 8 to 10 

 setre in the first to the sixth segment ; 6 to 1 in the tliree suc- 

 ceeding ones ; 4 or 5 in the tenth, and 3 or 4 in the last segment. 



The sette, figs. 3, 4, of the anterior segments are longest, and 

 range from about 0*15 to 0*25 mm. in length. They consist of a 

 long, straight rod, with a linear-lanceolate blade tapering into a 

 long filament. The rod varies little in length in the different 

 seta? ; but the blade varies considerably in this respect. The 

 blade is more or less bent from the rod, and is longest in the 

 longer setoe. 



Except the head and the first setigerous segments, the others 

 are provided on each side with a fascicle of podal hooks, which 

 are situated ventrally behind the bottom of the podal sette. The 

 hooks are 4 or 5 in each fascicle in the setigerous segments from 

 the second to the eighth inclusive, and are very different from 

 those of the succeeding segments. The podal hooks, fig. 5, of the 



