POLYCH/TCTA. 285 



sometimes simple, sometimes multiple (Plate IV., fig. 106). The arrangement of the 

 eyes is the same as in CEnone diphyllidia, and they can easily he found hy raising 

 the margin of the collar. The presence of the antenna? or occipital tentacles is the 

 one feature in which Aglaurides is helieved to differ from CEnone, and in view of the 

 ahsolute identity of the other parts this divergence appears remarkable. 



In Aglaurides, especially if the material he well preserved, the mere pulling hack 

 of the collar will not always suffice to discover the prostomial tentacles. I have 

 found it necessary to divide the collar hy a longitudinal incision before the antennae 

 come into view. They are extremely fugitive structures, not too easily found even in 

 half-macerated examples, so deep do they lie within the recesses of the nuchal sac. 

 In Aglaurides erijthrfeensis recently described by Gravier ['Arch. Mus. Paris' (4th 

 ser.), t. ii., 1900, p. 278] from the Red Sea the character of the jaw-pieces seems to 

 differ from that of the corresponding parts in A. fulgida. The reader is left with 

 the impression, that while " les pieces correspondantes sont plus developpe'es a droite 

 qu'a gauche," yet on the whole they are subequal, and only one half is figured on 

 the plate. Otherwise the species is indistinguishable from Aglaurides fulgida, the 

 shape of the head varying as mentioned above. The author does not mention the 

 radices maxillarum, which in A. fulgida are very long, longer than the rest of the 

 upper jaw, as in Maclovia and Holla, not short as they are in Lumbriconereis and 

 Lysarete. 



In addition to the characters presented by the antennae and the details of the 

 jaws as described and figured by Ehlers (' Borstenwurmer,' 18G8, p. 408) the genus 

 Halln (= CirrobrancJiia, Ehlers) differs from Aglaurides in having two entire 

 apodous segments behind the head, a peculiar processus oralis being furnished by the 

 first segment. A. fulgida has been recorded from Ceylon by Michaelsen, ' Jahrb. 

 Hamburg. Wiss. Anst.,' ix., 2, p. 99). 



Aracoda obscura, n. sp. Plate V., figs. 108 to 112. 



Station XLIIL, off Kaltura. A single specimen, incomplete behind, 16 millims. 

 long, L millim. wide, in an empty Pectinaria tube. 



Colour nearly black, with strongly iridescent tough cuticle. Prostomium pear- 

 shaped or conical, nearly equal to the four next segments (Plate V., fig. Ill) ; two 

 distinct achtetous segments in front, without processus oralis of the second segment. 

 The usual long posterior ligule on the parapodia. There are six or seven simple 

 curved limbate setae in the parapodium ; in some the limbus is nearly plain, in others 

 denticulate as shown in Plate V., fig. 112. The dilated portion of the setas is finely 

 and obliquely striated. 



The only way to identify the species of this and allied genera of Lumbriconcreida- 

 is by the character of the jaws. These are black and overlap, consequently they are 

 difficult to see in themselves and not easy to prepare from such a small specimen. 

 The principal feature in this case is provided by the jaw-pieces of the first pair which 



