LEODICID^E OF THE WEST INDIAN REGION. 



65 



In the type specimen the gills begin on somite 25 with a double filament, while they 

 appear as a single filament on the left of somite 24, becoming double in 25. The num- 

 ber of filaments is very irregular; on the right side of the type, for example, somites 25 to 

 34 show 2, 1, 1, 2, 2, 2, 2, 2, 4, 2 filaments, respectively. Together with this irregular 

 addition of filaments, there is an increase in length, though in the fully expanded; animal 

 the filaments do not meet over the mid-dorsal line (text-figure 212). The greatest num- 

 ber of filaments I could find in the type was five. Toward the posterior end the number of 

 filaments becomes reduced to one again, but this is longer than in anterior somites. The 

 last gill is on the twenty-fourth somite from the posterior end. On the base of the 

 posterior gills there is a prominent pigment spot. 



The first parapodium (text-figure 213) has the dorsal cirrus a little longer and more 

 pointed than the ventral one and with a conical post-setal lobe; it bears several aciculse. 

 The tenth parapodium (text-figure 214) has a dorso-lateral post-setal lip; the setal lobe 

 has two lips, one dorso-posterior and the other ventro-anterior. The dorsal cirrus has 

 a constricted base, then widens abruptly, becoming narrow toward the tip. The ventral 

 cirrus has a broad base of attachment and is bluntly rounded at the apex. There are 

 4 or 5 aciculse in the setal portion, but I could find no needle aciculae in the base of the 

 dorsal cirrus. A parapodium from the middle of the body (text-figure 212) shows a 

 rounded setal lobe whose anterior and posterior lips are about equal in length. The dorsal 



216 



TEXT-FIGURES 2 1 2 to 223. Marphysa viridis Tread well. 



212. Middle parapodium x40. 



213. First parapodium x34. 



214. Tenth parapodium x34. 



215. Dorsal acicula x310. 



216. Ventral acicula x310. 



217. Posterior parapodium x40. 



218. Simple seta x310. 



219. Compound seta x310. 



220. First kind of pectinate 



seta x394. 



221. Second kind of pectinate 



seta x394. 



222. Maxilla x20. 



223. Mandible x20. 



