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Kinberg's diagnosis, is characterised by an elongated body, with at least ei gh teen pairs of 

 elytra "dorsum non omnino tegcntia". 



Genus Gastrolepidia Schmarda '). 



. The sternum of the segments provided with a foliaceous appendage on each side. More 



than 2 1 pairs of elytra, covering the whole dorsum; from the 23<^ to the 35"^ segment the ely- 

 trophore-bearing segments alternate with two cirrophore-bearing ones, more posteriorly hovvever 

 the arrangement becomes irregular. 



I. Gastrolepidia clavigera Schm. 

 {G. ainblyphyllus Gr.) 



Schmarda, Neue wirbellose Thiere, 1861, p. 159, PI. XXX VI, fig. 315. 

 Grube, Annulata Semperiana, p. 46, PI. III, fig. 7. 

 WiLLEV, loc. cit. p. 253. 

 POTTS, loc. cit. p. 341. 



Stat. 60. Haingsisi, Samau Island. Reef. 6 specimens. 



Stat. 213. Saleyer Anchorage. Depth up to 36 M. i specimen. 



Gaspar Strait. 3° 27' Lat. S., 107° 5 1' Long. E. P. N. van Kampen, Oct. 1907. 2 specimens. 



In my opinion the prostomium more agrees with that of Lepidonohis than with that of 

 Harniotho'c as suggested by D.a.rboux-), for the lateral antennae are inserted upon the frontal mar- 

 gin ; however there occurs an annular constriction, that makes the insertion somewhat indistinct. 

 The unpaired antenna is about of the same length as the paired ones ; the palps also are provided 

 with a terminal flagellum like the antennae and the dorsal cirri. Willey first stated, that behind 

 the 23<ï segment not all the elytrophores regularly alternate with two cirrophores, for he found the 

 posterior elytra inserted upon segments 35, 36, 38, 39, 41, 43 and 45, and Potts, who could 

 examine several .specimens from Zanzibar, says that he could confirm Willey's statement and 

 that he found this distribution quite invariable. I regret that I cannot agree with his opinion,^ 

 for I found in one specimen with 52 segments and 30 mm. in length, the elytra inserted 

 upon segments 35, 36, 38, 39, 42, 44, 46 and 48, whereas in a smaller specimen with 44 

 segments and 20 mm. in length, they are situated on segments 35, 36, 39, 41 and 43. In 

 the posterior part of another specimen, 19 mm. long, the elytra were distributed on segments 

 35, 36, 38, 39, 42, 43, 45, 46, 47, 5i and 54. 



Schmarda already mentioned that the colour of this worm is very variable, but Potts 

 first observed, that this is due to its association as a commensal with holothurians, the colour 

 of which it matches ; when found on Holothuria atra (as the specimens from Haingsisi) its 

 coloration is of a deep purple-black, with white spots upon the elytra and white tip of the 

 dorsal cirri, but associated with light-coloured Holothurians {Hol. maailata a. o.) it undergoes 

 a corresponding colour-change. 



1) Neue wirbellose Thiere, 1861, p. 159, I'l. XXXVI, fig. 315. 



2) 1,0c. cit. p. 105. 



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