292 PROCEEDINGS OF THE ACADEMY OF [April, 



the jaws. Ehler's figure of the latter differs in certain respects so 

 greatly from the form usual in the genus that I have assumed that the 

 single specimen available to him was abnormal or imperfect in these 

 respects. Otherwise these specimens could scarcely be regarded as 

 cospecific with his, notwithstanding their close external similarity. 

 Even on this assumption there is by no means complete identity, and 

 further study of Chilean material may necessitate subspecific or even 

 wider separation. 



A set of well-preserved jaws is represented in figures 141, 142, and 

 several others which were dissected agree closely, the principal differ- 

 ences being in the occasional presence of a third large tooth in place 

 of the first small tooth on one of the large-toothed maxillae (II) and 

 in the variable length of the stems of the mandibles. 



The peristomium of Ehler's type is decidedly more elongated than 

 that of the Californian examples, in which the basal width equals the 

 length. 



Parapodia of the anterior, middle and posterior regions are illus- 

 trated in figures 135-137. Those of the latter region with their two 

 cirriform processes are very characteristic and bear a very close 

 resemblance to Ehler's figure, which, however, is inverted. The 

 ventral outstanding filamentous process is postsetal and the dorsal 

 erect one, which contains a conspicuous vascular loop, is presetal in 

 origin. The notopodial tubercle or rudimentary cirrus is quite distinct 

 from the latter, but becomes obsolete on posterior segments. Para- 

 podia exhibiting this extreme development of the lobes are confined 

 to the posterior third or two-fifths of the body, those in the middle 

 region having them digitiform and only about as long as the body of 

 the foot (fig. 136) and in this respect these specimens differ somewhat 

 from Ehler's, in which the filiform character becomes established 

 farther forward. This difference, though somewhat indefinite, is quite 

 striking and is equally true of large and small specimens alike. The 

 resemblance of the bidigitate parapodia of the middle region to those 

 of L. bifurcata Mcintosh is striking and, indeed, the two species have 

 much in common, but they diverge in the character of the posterior 

 parapodia (fig. 137). 



Although the setae (PI. XX, figs. 138-140) in general resemble those 

 of the type in form and distribution, in respect to the latter there are 

 some noteworthy variations and differences. Anterior parapodia 

 bear both limbate setae and crochets, the latter being themselves 

 limbate, slender and with small imperfect heads; posteriorly only 

 true hooded crochets with short bodies and strongly hooked heads 



