212 PROCEEDINGS OF THE ACADEMY OF [1883. 



sents the usual form of the cephalic eye. Figs. 21 and 22 represent 

 the two eyes ofi the same individual, the right eye apparently 

 double. Fig. 23 represents another double eye, but with the lens 

 directed backward. Fig. 24 represents a caudal eye. 



The tube of Fahricia is composed of exceedingly fine particles 

 of quartzose sand and indefinite particles of mud. 



I observed no specimens of this genus, exhibiting the repro- 

 ductive organs in the condition usual in mature ones of Mana- 

 yunkia. 



In several instances I observ^ed a few free eggs and young worms 

 of 0'12 mm. in length within tubes in company with the parent, 

 but did not have the opportunity of investigating them. 



Manayunkia mainly differs from Fahricia in having a pair of 

 simple or undivided tentacular lophophores instead of having 

 them trilobate ; in the possession of an inner pair of larger ten- 

 tacles which receive a continuation of the main trunks of the 

 vascular s}- stem ; and in having no eyes to the terminal segment 

 of the body. 



EXPLANATION OF THE FIGURES OF PLATE IX. 



Fig. 1. Manayunkia sPECfOsA. Magnified about 50 diameters. The 



worm in the ordinaiy condition of extension, with its tentacles 



spread. 

 Fig. 2. A stock of five tubes. Magnified about 4 diameters. 

 Fig. 3. One of the longer podal setse from the second setigerous segment 



of tlie body. 666 diameters. 

 Fig. 4. One of the shorter podal setae, from the same. 666 diameters. 

 Fig. 5. A podal hook, from the same. 666 diameters. 

 Fig. 6. A row of podal hooks, from the last segment of the body. 250 



diameters. 

 Fig. 7. A podal hook from the same row. 666 diameters. 

 Fig. 8-13. Egg and different degrees of development of the young of 



Manayunkia. 100 diameters. 

 Fig." 14-16. Podal setae oi. Fahricia Leidyii, Verrill. 500 diameters. 

 Fig. 17, 18. Podal hooks of anterior segments. 500 diameters. 

 Fig. 19. Podal hook of posterior segment. 666 diameters. 

 Fig. 20-24. 'Eyes of Fahricia. 250 diameteis. 

 Fig. 20. A cephalic eye of the usual form. 



Fig. 21, 22. Ri^ht and left cephalic eyes of the same individual. 

 Fig. 23. A double cephalic eye. 

 Fig. 24. A caudal eye. 



