112 



LEODICID.E OF THE WEST INDIAN REGION. 



first somite is 1.5 mm. wide and is not sharply separated from the prostomium. There 

 is a gradual increase in width to the end of the anterior third of the body, where it is 

 2 mm. wide. The living animal much resembles Lumbrinereis or Arabella, with which 

 it occurs in the sand, but is much darker brown in color than either of these. After 

 preservation the anterior end is light brown with some iridescence, but in the region of 

 somite 40 this coloration becomes much deeper and the iridescence is less marked. 

 The extreme posterior end is a lighter color. The pygidium was regenerating in all 

 specimens collected, and therefore I have no information concerning the anal cirri. No 

 drawing of the living animal was obtained. 



In the anterior portion of the body the parapodia practically do not exist, the setse 

 arising in a tuft from the side of the body. In the region of the forty-fifth somite the 

 parapodia become recognizable, each with a minute posterior lobe. Farther back this 

 lobe increases in size and becomes more prominent than the setal portion. Text-figure 

 418 is taken from a parapodium posterior to the one-hundredth. A single heavy, 

 pointed acicula protrudes to a considerable distance from the apex of the parapodium 

 and there is a tuft of simple setae. The setse (text-figure 419) are similar throughout 

 the entire extent of the body, differing only in the length of the shaft. The apex is 

 curved, sharp-pointed, and has a large wing along the convex surface. 



The maxilla (text-figure 420) has a small carrier with slender prolongations, united 

 near their middle by a brownish plate of chitin. 



The forceps has heavy bases on which I could see no trace of denticulations, and 

 each base carries on its outer posterior angle a 

 slender rod directed posteriorly. The apex of each 

 half is much bent and is sharp-pointed. 



The paired plates are noticeably merely the 

 darkened and toothed inner margins of chitinous 

 sheets which extend laterally, becoming much 

 lighter on the side away from the teeth. I have 

 drawn only the pigmented portions. These are 

 curved so that their appearance varies with their 

 position. In the normal position they are bent 

 upward or toward the observer, and in this posi- 

 tion their inner margins appear smooth. I have 

 represented them as they appear when rolled so 

 as to show the teeth. The proximal plates have 

 a terminal large tooth, then one smaller one, then 

 two larger followed by two smaller ones. The 

 plates of the second and third pair have each a 

 large terminal tooth with at least two much smaller 

 ones, and these are followed by minute denticu- 

 lations of the margin. In the specimen figured 

 there was a single unpaired plate distal to the third 

 right paired one, but this did not appear in another 

 specimen dissected at the same time. A triangular 

 plate of dark chitin is attached to the ventral sur- 

 face of the carrier, but there is no trace of mandib- 

 ular plates. 



Collected in April 1918, in sand, in Buccoo 

 Bay, Tobago. 



Type in the American Museum of Natural 

 History. 



TEXT-FIGURES 41S to 420. 

 Drilonereis brunnea Treadwell. 



418. Parapodium xSO. 



419. Seta x210. 



420. Maxilla x55. 



