BY T. HARVEY JOHNSTON AND O. W. TIKGS. 215 



misakiensis Ikeda. The known distribution of B. minor is 

 remarkable, viz., Mediterranean (Bay of Naples and Marseilles) 

 and the Loochoo (Riukiu) Islands, off Formosa. Ikeda, however, 

 refers (1904, p. 72) to certain differences in regard to the anal 

 vesicles, so that it is not improbable that he was dealing with a 

 distinct though closely related species. 



PSKUDOBONELLIA BIUTERINA, 11. gen. et Sp. 



During a visit in August, 1915, to North- West Islet, and in 

 1917 to Masthead Islet, two of the Barrier Reef atolls belonging 

 to the Capricorn Group, situated due east from Keppel Bay, 

 Queensland, some remarkable echiuroids were found which, from 

 their external appearance, were then regarded as a small species 

 of Bonellia, but subsequent examination showed anatomical dif- 

 ferences of such a nature that it has been deemed necessary to 

 propose a new genus for their reception. In general appearance, 

 size, and colour, they remind one of the Japanese B. minor. 

 They have, moreover, a similar habit, occurring between tide- 

 marks on the coral reef flats and in boulders, with the dark green 

 body hidden in crevices in the dead coral, from which the rather 

 more lightly-coloured, bifurcated proboscis can be protruded for 

 a considerable distance. 



The size of the female varies within rather wide limits, due, 

 no doubt, to differences in age. In specimens preserved in 

 formalin, the body length ranged from 1-5 to 2-6 cm. and the 

 breadth from 0-4 to 08 cm. Accurate measurements of the 

 living proboscis were not made, but the organ was capable of 

 extension to about 10 cm. In preserved material it varied in 

 length from 1 to 3 cm., while the bifurcations reached from 0'4 

 to 2 cm. according to the degree of contraction. 



The body is somewhat sack-like, broader posteriorly than in 

 front (Plate ix., figs.l, 2). The groove on the ventral surface of 

 the proboscis is broad and shallow distally, becoming deeper and 

 more prominent as it approaches the mouth. At about 2 mm. 

 behind the latter lie the ventral seta?. The external openings of 

 the uteri were not recognisable in entire specimens, but in one 

 out of twenty-six worms examined, there was to be seen a dis- 



