94 LEODICID.E OF THE WEST INDIAN REGION. 



Subfamily LUMBRINEREINjE. 



(Genera represented in this paper.) 

 Dorsal cirrus rudimentary. 



Posterior border of mouth formed in part by a prolongation of second somite. Both capillary and 



hooked setae Lumbrinereis 



Posterior border of mouth not formed by second somite. Only capillary setae present. Often with eyes. 



Maxillary plates small, the terminal ones mere hooks Drilonereis 



Maxillary plates large, denticulated, sometimes asymmetrical Arabella 



Dorsal cirrus foliaceous. 



Three tentacles covered by the border of the prostomium Aglaurides 



Genus LUMBRINEREIS de Blainville. 



H. M. de Blainville, Dictionnaire des Sciences Naturelles, 1828, p. 486. 



Body elongated, slender, without prostomial appendages, gills, or parapodial cirri, 

 but with anal cirri. The first somite interrupted ventrally by a prolongation of the 

 second somite to form a portion of the posterior border of the mouth. Maxilla of short 

 carriers, forceps, and three sets of paired plates, the proximal ones toothed, the others 

 much smaller. Mandible about as long as maxilla, its anterior margin broad, narrowing 

 decidedly posteriorly, the two halves more or less fused. Setse compound, simple, and 

 hooked. 



Blainville's original spelling was Lumbrinereis. This, apparently for philological 

 reasons, was changed by Grube (1851, p. 45) to Lumbriconereis, which term has been 

 generally employed ever since. The original spelling should be retained. Grube (1879, 

 p. 80) distinguished between Lumbriconereis with 4 pairs of plates in the maxilla and 

 Larymna of Kinberg (1864, p. 572) with 5 pairs. Gravier (1900, p. 222) makes this 

 same distinction and puts Zygolobus of Grube (1863, p. 40) under Larymna. Even 

 though Kinberg makes the further distinction that the base of the forceps is smooth 

 in Lumbriconereis and toothed in Larymna, ifc seems to me that the differences are 

 scarcely sufficient to be of generic importance. I have not, however, seen any specimens 

 of Larymna. 



Lumbrinereis branchiata, new species. 



(Plate 8, figures 5 and 6; text-figures 333 to 343.) 



A smaller species than L. nuchalis (see p. 104), much resembling L. Candida (see p. 96) 

 in general appearance, especially in a grayish tint due to a dusting of fine spots. Pre- 

 served material shows no especial color characters, but the species may be recognized 

 by the rounded lobes (gills?) occurring in the region just behind the middle of the body. 

 In the process of preservation the specimen figured lost the last few somites with the 

 pygidium. What remained measured 350 mm. and contained about 500 somites. The 

 prostomial width was less than 1 mm. and the greatest body-width about 2 mm. 



When fully expanded the prostomium is an elongated cone (plate 8, figures 5 and 6) 

 wider at base than the somites just following it. When contracted it is about the width 

 of the peristomium. In later somites there is a gradual increase in width at first and a 

 noticeable narrowing toward the posterior end. There are two pairs of equal, conical 

 anal cirri. 



The first parapodium is very minute, the first set appearing as if they arose directly 

 from the body-wall. The tenth (text-figure 333) is well developed, with a setal and post- 

 setal lobe and a vertical row of setae between them. A parapodium from behind the 

 middle of the body (text-figure 334) has slender lobes, the posterior much longer than the 

 setal. In this region many somites have on their dorsal posterior outer angles (see figure 

 5, plate 8, in upper right-hand corner, and text-figure 335, a dorsal view of two somites) 

 a flattened expansion which in the living animal is filled with blood and evidently func- 

 tions as a gill. These seem variable in their occurrence and may be retractile. 



