78 ALICE L. EMBLETON ON THE STKUCTUEE AND 



The only previous description of this species is that given by Drasche *, who had but 

 two specimens to work on, with the result that his observations are superficial and 

 limited to three imges. Of his specimens be records : " Beide Exemplaren fehlte der 

 Kopflappen (Riissel)." It may be that, having so little material, he was misled by the 

 highly retracted state of this organ, wliich, possessing as it does a very powerful 

 musculature, is very liable to extreme contraction. Even allowing for the contracted 

 condition, this proboscis is a much shorter organ than in Echlurus Pullasli, or Thalassema 

 neptuni, and never assumes the almost ribbon-like form it presents in the latter 

 species. 



At the base of the proboscis-lobe is the mouth, placed ventrally (Pi. 7. figs. 1, 2, m.). 



The whole outer surface of the body is densely papillated (PL 1. figs. 1, 2, 4), agreeing 

 in this respect with other species of Echiurus; the papillae show no very definite 

 arrangement, though they tend to run in transverse rows round the body, in wliich 

 direction also the individual papillae are elongated (PL 7. fig. J.). 



As in allied forms, anteriorly on the ventral surface are two recurved setae (PL 7. 

 fig. 1, s.a.), pointing outwards and backwards ; posteriorly are the characteristic peri-anal 

 hooks (fig. 1, s.p.), which in this species form but a single circlet. Drasche gives 

 this as one of the three distinguishing features of the species — hence its name 

 " unicinciiis" or "one girdle." In speaking of this circlet of setse, however, he says 

 it is made up of 11 setaj ; but on examining my material the number seems to be by no 

 means constant, varying indifferently from 10 to 13 (PL 7. figs. 1, 5). The space 

 between the two setae situated most ventrally is always greater than that between any 

 other tw^o, giving it the appearance of an incomplete ring — though Drasche has observed 

 that the ring is complete ventrally. 



Just behind the two anterior hooks, on the ventral side, it is possible to see with a 

 hand-lens two pairs of minute pores among the papilke ; these are the external apertures 

 of the segmental organs or nephridia. The reproductive prodvicts are passed to the 

 exterior through these pores. 



Referring to the papilhe, Drasche says : " Nur an einer Stelle etwa 5 mm. hinter den 

 Bauchborsten, findet sich eiu 5h mm. breiter Giirtel von 13 Papillenkrauzen. Diese 

 Papillen sind etwas grosser als die iibrigen und habeu die Porm von auf die schmale Seite 

 ijestellten Ziegeln." 



So far as my specimens are concerned no such tract is discernible, though on 

 submitting the body-wall to microscopic excxmination it is found that in the region of 

 the segmental organs the ordinary unicellular glands occur along with immense 

 compound glands (which will be more fully dealt with below). This particularly 

 glandular belt may correspond to the 13 rows of large papillte mentioned by Drasche 

 (PL 7. figs. 6, 7, £r.). 



Probably the aoimal secretes a substance with which it lines the tubes or burrows in 

 \\hich it lives, using the two recurved anterior setae in climbing and its posterior circlet 



* "Ueber ciue ueue Echiurus-A-ti aus Japan," Verhandlungen des zoologisch-botanischen Vereins in Wien, 

 Band sxx. 1880. 



