74 



LEODICID^ OF THE WEST INDIAN REGION. 



The gills begin as a single filament on about the sixtieth somite; the number is 

 increased to two filaments at about the eightieth somite, and gills extend to about fifty- 

 somites from the posterior end, the last few having only one filament (text-figure 259) 

 from region of somite 110. 



The first parapodium (text-figure 260) has a pointed posterior lip which is slightly 

 asymmetrical, a long dorsal, and an oval ventral cirrus. Two small aciculse extend to 

 the surface between the two lips of the setal portion. The tenth parapodium (text- 

 figure 261) has a relatively smaller dorsal cirrus; the ventral cirrus is a conical swelling at 

 the end of a pad-like structure. The posterior lip is asymmetrically pointed ; the end of 

 the setal portion between the anterior and posterior lobes is rounded. Three dark-brown 

 aciculse reach the surface just behind the anterior lip. A later parapodium (text-figure 

 259, of about the one hundred and tenth) has a pointed setal lobe with little difference 

 in the length of the anterior and posterior lips, a single strong acicula reaching the surface 

 at the apex of the lobe, and a hooked ventral acicula which is much smaller than the 

 dorsal. The dorsal cirrus is a very small conical structure and the ventral cirrus is also 

 reduced to a small cone. In the entire animal the base of this cirrus is continued into a 

 swelling which extends across toward the ventral midUne. The gill-filaments are straight 

 and of equal length, arising from the surface of the body dorsal to the insertion of the 

 dorsal cirrus. 



There are at least three kinds of setse in the first parapodium: the compound (text- 

 figure 262), each with a slender shaft, terminating in a single tooth, and denticulated 

 proximal to this, the terminal portion slender with apical and subapical teeth covered by 



Text-figures 257 to 268. Marphysa languida Treadwell. 



257. Head x6. 



258. Pygidium xl3. 



259. One-hundred and tenth parapodium x30. 



260. First parapodium x60. 



261. Tenth parapodium x60. 



262. Compound seta from first parapodium x334. 



263. Second form of compound seta from first 



parapodium x354. 



264. Compound seta from middle of body x354. 



265. Simple seta from middle of body x334. 



266. Apex of dorsal acicula x200. 



267. Apex of ventral acicula x200. 



268. Pectinate seta x666. 



