74 THE ANNELIDA POLYCHAETA. 



the point of emergence and the head or pectinate division toward which it 

 thickens shghtly. The head is bent at a small angle to the shaft as usual. It 

 narrows to a rounded point distad and is gently concave on the side bearing 

 pectinae and coiivex on the opposite ; it presents an acute subapical tooth which 

 diverges but little from the principal tooth. The pectinae extend about half- 

 way from the base to the apex, sometimes a little more and sometimes a little 

 less. (Plate 8, fig. 8; Plate 9, fig. 1, 2). 



The elytra are firmly attached and are strongly imbricated. Those of the 

 first pair are small and subcircular in outline; a rather narrow border on each 

 is smooth or only very minutely granular, while the large area within is thickly 

 studded with large tubercles or papillae which are subcorneal, the distal portion 

 being softer and a basal portion denser and more opaque and appearing by itself 

 hemispherical; the papillae seem to be all of the same type excepting for varia- 

 tion in size, those toward the periphery of the papillose area becoming smaller. 

 The succeeding elytra become much larger in size and are more elongate, being 

 broadly subelliptic to subovate. On the second elytra large papillae similar 

 to those of the first occur over and immediately adjacent to the area of attach- 

 ment, but elsewhere the papillae are much reduced and anteriorly especially 

 are sparse, leaving considerable areas smooth. Toward the middle region and 

 farther caudad the elytra become almost smooth, losing the larger papillae, while 

 the smaller ones become reduced to minute granule-like bodies which may be 

 present only on restricted areas of the surface. There are fifteen pairs. (Plate 



9, fig. 4, 5). 



Locality. — Lower California: Santa Margarita Island. Exped. 1891. 

 One specimen which at some time had apparently been dry. 



As a species characterized especially by the structure of the setae and 

 elytra. 



Lepidonotus Leach. 



Ann. philos, 1819, 14, p. 205; DARBOtJx, Bull. sci. France & Belgique, 1903, 30, p. 109 (in part); Mc- 



Intosh, British annelids, 1900, 1, pt. 2, p. 273. 

 Eumolpe Blainville, Diet. sci. nat., 1828, 57, p. 457 (in part). 



Lepidonotus johnstoni Kinberg. 



Ofvers, K. vet. akad. Forh., 1855, 12, p. 381; Fregatt. Eugenies Resa. Zool. Annulater, 1857, pi. 4, f. 

 13-1.3b; 1858, p. 12; 1910, pi. 10, f. 15; Baird, Journ. Linn. soc. London. Zool., 1865, 8, p. 182. 



Locality.— Off Panama: Perico Island. Shore. 26 October, 1904. One 

 specimen. 



