272 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



Distribution. — Haploscoloplos fragilis is common in intertidal sandy 

 shores from New England south to southern Florida and in the Gulf of 

 Mexico. 



Haploscoloplos robustus (Verrill) 1873 

 Plate 25, figs. 4-6 



Anthostoma robustum Verrill, 1873, pp. 597-598, pi. 14, fig. 76; Web- 

 ster, 1879, p. 258. 

 Scoloplos robustus Verrill, 1881, p. 301. 

 Scohplos robusta Webster and Benedict, 1884, p. 724. 

 Scoloplos bustorus Eisig, 1914, pp. 422-423; Hartman, 1942a, p. 58, 

 figs. 110-112; Hartman, 1944a, p. 340; Hartman, 1945, p. 30. 

 Scoloplos rufa Tread well, 1941b, p. 1, figs. 1-6. 



Haploscoloplos bust oris Horn and Bookhout, 1950, pp. 1-9, pis. 1-4. 

 Haploscoloplos robustus Hartman, 1951, p. 78, pi. 21, figs. 4-6; Hart- 

 man, 1956. 

 Collections. — Many individuals from intertidal sandy beaches are 

 from Massachusetts south to North Carolina; others are from the Gulf 

 of Mexico. 



This grossly resembles H. fragilis (see above), with which it some- 

 times occurs, but it is a larger species and easily distinguished by its 

 having no ventral and subpodial lobes such as are present in H. fragilis. 

 The prostomium is less acutely pointed. The first branchiae are present, 

 though small, at about segment 23 and they rapidly increase in size so 

 that they stand erect over the dorsum. Transition from thorax to ab- 

 domen is about at segment 22 to 24 or somewhat farther back. Inter- 

 ramal cirri are first present from the first branchial segment and con- 

 tinue back through many (about 54) segments; they are absent farther 

 back. 



Thoracic neuropodia have a small short papilla at the midlength of 

 the postsetal lobe ; the corresponding notopodia have a larger and broader 

 process, also near the middle of the parapodial ridge. Abdominal neuro- 

 podia have a conspicuous transverse flange (figs. 5, 6) ; in ovigerous indi- 

 viduals it is greatly distended due to the presence of great numbers of 

 gonadial products. 



Anthostoma robustum Verrill was thought to be a homonym of 

 Alcandra robusta Kinberg (1866) by Eisig (1914, p. 422), who pro- 

 posed the specific name bustorus. Since Verrill's species rightly goes to 

 Haploscoloplos and Kinberg's species is in another genus (Hartman, 

 1948b, p. 106), the change in specific name is unnecessary. 



