210 PROCEEDINGS OF THE ACADEMY OF [1883. 



It measured one-third of a millimetre in length. The bodj'-wall 

 and intestine are quite distinct, the latter exhibiting eight seg- 

 ments. Tiie tentacular lobes have commenced development. Fig. 

 12 represents an individual further developed, from the same tube 

 as the former. It measured half a millimetre Ipng. The body is 

 distinctly divided into nine segments, of which eight bear a pair 

 of setae on each side. The tentacular lobes exhibit each the rudi- 

 ments of four tentacles. Eyes also have made their appearance. 

 Fig. 13 represents a young worm, from another tube, the only one 

 accompanying its parent. It measured 0*72 mm. long. The body 

 is divided into the same number of segments as in the former. 

 The tentacular lobes have developed each four tentacles with the 

 rudiment of a fifth. Podal hooks could be detected in none of the 

 segments except the last, in which there were three comb-hooks on 

 each side. Another young individual observed, from another 

 tube, about the same size of the preceding, had five tentacles on 

 each side, but was otherwise exactly similar. Another individual 

 three-fourths of a millimetre long, with five tentacles on each side, 

 had one more setigerous segment than in the others. 



The species of Fahricia to which I referred in the beginning of 

 the present communication, and which I examined with pai'ticular 

 interest on account of the near relationship of Manayunkia to it, 

 is the same as that described by Prof. Verrill, as being common 

 from New Haven to Vineyard Sound and at Casco Bay (see Report 

 on the Sea Fisheries of New England, Washington, 1873, p. 619). 

 I first noticed the worm at Newport, Rhode Island, in 1858, and 

 found it abundantly at Bass Rocks, Gloucester, Mass., in 1882. 

 It occurred on rocks between tides, under a luxuriant growth of 

 Fucus vesiculosus, With, its tubes projecting from among the mud 

 and sand firmly' fixed together with multitudes of little mussels 

 about the roots of the sea-weed. 



The worm is three or four millimetres long and of a yellowish 

 or yellowish brown hue, with more or less reddish. The body is 

 compressed cylindrical and slightly tapering behind, and is 

 divided into twelve segments, including the head. This is pro- 

 longed dorsally in a half elliptical process or upper lip. The 

 vertex supports on each side a trifurcate lophophore, each fork 

 of which is provided with a double row of narrow cylindrical 

 tentacles invested with cilia. 



