THE P0LYCH2ET0US ANNELIDS OF PORTO RICO. 
203 
ANTHOSTOMA Schmarda. 
Anthostoma ramosum Schmarda. 
Anlhostoma ramosum Schmarda, Neue Wirbellose Thiere, p. 62. Webster, Annelids from Bermuda, p. 321. 
So far as I can tell from Schmarda’ s brief description, these belong to his species. Head 
rounded, almost semicircular in form. Proboscis in form of three broad plates, one much larger than 
the other two. Each much subdivided, colorless at base, dark-brown at apex. Body very much 
flattened and broad back to segment 34, with very short gills, leaving more than half the dorsal surface 
exposed. At about thirty-fourth segment it becomes narrower, looking as if dorsal surface of para- 
podium had rolled upward, and the gills elongate so as to cover whole of dorsal surface. The gills 
begin on the fourth setigerous segment. 
If 1 have correctly identified this specimen, Schmarda’s description and figure of the parapodium 
applies only to the posterior segments, and here the dorsal gill is relatively too small in his figure. 
Anteriorly the parapodia contain from 9 to 13 stout setae. Only at the posterior end is the number 
as low as 4, as Schmarda has described. 
Collected from Arroyo and Boqueron Bay. 
Anthostoma latacapitata, n. sp. 
Head nearly four times broader than long, anterior edge nearly straight, angles rounded. No 
eyes. (Fig. 61). First segment twice as wide as head, second segment (first setigerous) a little wider 
than first, and succeeding segments of equal width with this, back to segment 25. Here the body 
narrows very slightly and remains of a uniform width throughout. Setigerous segments as far as 
twenty-third (fig. 62), with a broad dorsal cirrus ( “second gill”) and dorsal bundle of long, delicate 
65 
63 
Figs. 61-65 . — Anthostoma latacapitata. Fig. 61, Anterior 
seta, x 330. Fig. 64, Bifurcated seta, 
setae, each with numerous fine parallel transverse markings (fig. 63). A single one of these was 
bifurcated at end (fig. 64) . On ventral ramus a prominent posterior lip, its dorsal angle prolonged into 
a conical point (fig. 62). ' This lip is marked off posteriorly by a short constriction from the para- 
podium. Ventral setae very numerous, forming a dense comb-shaped row. Setae stout, narrowing 
rapidly to an acute point, which may be bent, or completely curved on itself, the stem marked with 
numerous transverse lines (fig. 65). In figure of parapodium only a few of these are represented. 
Dorsal gills begin on sixth segment. They are linear, with acute ajiex. Behind twenty-third 
segment the ventral row of setae becomes much shorter, and throughout the greater part of the body 
the posterior lip of ventral ramus is ovate with acute tip. Anterior lip more prominent than anteriorly. 
Setae of ventral ramus of two kinds. A few (two) blunt, rounded, hardly reaching beyond apex of 
anterior lip, and ten to twelve delicate, long, finely toothed, with transverse lines like those of anterior 
dorsal setae. Dorsal cirrus shaped like anterior ones, but much smaller, and dorsal gill proportion- 
ately much larger than anteriorly. Very thick at base, tapering rapidly to -apex, and extending for 
one-quarter of its length beyond dorsal cirrus. In the preserved specimen these dorsal gills are bent 
backward and slightly outward, leaving dorsal surface of body uncovered. Proboscis only slightly 
protruded, edges of protruded portion ramose. 
