34 THE ANNELIDA POLYCHAETA. 



spicuous bud-like expansion which is drawn out into an acute point. The 

 branches of adjoining branchiae intermingle so that when a series is viewed 

 from above only a continuous brush-like band appears, the separate branchiae 

 not being distinguishable in dorsal view. 



The cirri are simple thread-like structures which do not surpass the branchiae 

 in length. The dorsal and lateral or intermediate cirri are similar. The lateral 

 dorsal cirrus is inserted opposite the fourth (or third?) branchia. 



The dorsal setae extend in transverse series parallel with the row of branchiae 

 entirely across the dorsal ridge to the outermost branchia and are not separated 

 by any distinct empty space from the lateral setae. The principal dorsal setae 

 rise clearly above the tops of the branchiae. Each is forked in the usual way. 

 The principal prong is long and straight or with a weak double curve. The 

 smaller branch curves a little outward. (Plate 12, fig. 3). Both prongs are 

 wholly smooth. In a second type of dorsals the setae are similar excepting for 

 being shorter and finer. (Plate 13, fig. 4). In addition there are characteristic 

 short dorsal setae which are strongly clubbed at the distal end. In these the 

 distal enlargement is cleft from one side in a plane that curves caudad, sepa- 

 rating a lower lobe with convex inner face from an upper one with concave 

 inner surface. The inner surface of each of these lobes is transversely ridged 

 along each border. (Plate 12, fig. 7; Plate 13, fig. 1, 2). Somewhat similar setae 

 exist in E. triloba Ehlers and in E. myrtosa (Savigny). The upper ventral setae 

 are as long as the dorsals, the lowermost much shorter. They are similarly 

 furcate but are rather more slender. As with the dorsals, no teeth occur on 

 the prongs. In the shorter ventral setae the principal prong may have but 

 a single weak curve, or it may be straight and acute; while the minor prong 

 may be reduced to a minute acute tooth. (Plate 13, fig. 5, 6). 



Locality. Panama: Perico Island. Shore. 26 October, 1904. Two 

 specimens. 



This species in the general character and number of its branchiae approaches 

 E. capensis Kinberg. The latter is larger (40-50 mm.) with a much larger 

 number of somites (between fifty and sixty). The ventral setae have their 

 prongs serrate instead of wholly smooth. The caruncle is longer, extending 

 over eight somites instead of only five. That species would seem also to lack 

 the characteristic clavate dorsal setae. The present species also has close 

 similarities to E. Umbata Moore; but in the latter there is but one type of setae, 

 the peculiar cleft clavate form being absent and the branchiae seem not to have 

 the conspicuous, bud-like terminal enlargements. 



