LEODICID.E OF THE WEST INDIAN REGION. 61 



five branches in the gills of M. acicularum, and these are long and slender, arising from 

 a rapidly diminishing base (text-figure 186), those of the variety (text-figure 194) are 

 shorter, arise from the side of a base of nearly uniform diameter, and may have as many 

 as eight branches. They extend farther posteriorly than in M. acicularum (compare 

 figure 5 with 1, plate 5) and retain their branched condition to a much later somite. 

 From the surface of the body this gill difference is the most convenient method of 

 distinguishing the species from the variety. 



The maxilla (text-figure 195) has a rather large carrier. In the forceps the basal 

 portion extends for nearly one-half its length, the terminal portions are slender and 

 much curved. The carrier is dark brown with black margins, while the forceps is nearly 

 black. Each proximal maxillary plate has 6 prominent teeth, the distal plates being 

 rather small, with 9 teeth on the right and 3 on the left. The unpaired plate has 8 

 teeth. The terminal pigment patch on the right is larger than that on the left, and 

 there are two small, non-pigmented chitinous plates, one on either side of the termina' 

 paired. The mandible (text-figure 196) is very dark-colored with longitudinal patches 

 of a lighter brown toward the anterior end, the beveled portion marked with concentric 

 black lines and washed with white. The distinction between this jaw apparatus 

 and that of M. acicularum can be easily seen by comparing figures 188 and 189 with 

 195 and 196. By bending back the lower lip the mandibles can be exposed and the 

 species be distinguished from the variety by the characteristic structure of their ante- 

 rior ends. 



The setse are very similar to those of the species, though more slender. (Compare 

 figure 197 with figure 190 for the compound setae, and figures 198 and 192 for the simple 

 ones.) In the variety the pectinate setse of the anterior somites are very like those of 

 the species but have fewer teeth, while in the posterior somites they become broader, 

 the teeth are much larger, and the terminal teeth are relatively shorter. A similar but 

 less noticeable change occurs in the pectinate setse of the species. 



The aciculse are similar to the dorsal ones in the species, there being no bifid ones 

 in the ventral bundle. 



Marphysa belli Audouin et Milne Edwards, var. oculata, new variety. 



(Plate 5, figures 13 and 14; text-figures 201 to 211.) 

 Bibliography for Marphysa belli. 



Eunice belli Audouin et Milne Edwards, 1834, p. 149, plate in, figures 1 to 4, 8, 9. 

 Marphysa belli Quatrefnges, 1865a, volume 1, p. 333. 

 Marphysa belli v. Marenzeller, 1874, p. 59. 

 Marphysa belli Ehlers, 1887, p. 95, plate 28, figures 1-8. 

 Marphysa belli de St. Joseph, 1888, p. 204. 



Marphysa belli Mclntosh, 1910, p. 448, plate LV, figures 5, 6; plate. LX, figure 12; plate LXIII, figures 2, 

 2a; plate LXV, figures 11, lla; plate LXXXVI, figures 3, 3d. 



A single incomplete specimen was collected at Mangrove Key in Key West Harbor 

 in June 1915. The body retained approximately 100 somites, was about 70 mm. long, 

 with a peristomial width of 1.5 mm. 



There was no definite pigmentation, though the anterior part of the body is darker 

 than the posterior and there was a marked iridescence (plate 5, figure 13). The pro- 

 stomium is rounded, with a very faint indication of a median fissure. The tentacles 

 are pointed, extending beyond the prostomium, the median and the inner paired about 

 equal in length, the outer paired shorter. In the preserving fluid the tentacles contracted 

 so as to be shorter than the prostomium. There is one pair of prominent eyes. 



The peristomium (plate 5, figure 13) is about as long as the prostomium, and not 

 more than one-third longer than somite 2. Behind this point the body gradually widens 

 to about the fifteenth somite, where it is approximately 2 mm. broad, and this diameter 



