310 F. F. LAIDLAW. 



its edge, but the majority into any holes on its surface. If however the hand is placed 

 over one, it will remain contented for some time in any damp spot and will not come into 

 the light. That the latter in any strength is what the animals object to is clear, as in 

 glass vessels they always get to the side away from it and hide under the lee of any stones 

 which may be placed in the water. 



" It is noteworthy that the Turbellaria do not generally occur on reefs or reef-patches 

 within the lagoons, nor indeed where there is not an ample change of water. The animals 

 are never found on growing coral, perhaps on account of the light. 



"The colours are in no sense protective, nor do I think they can be warning. I have 

 never seen, either on the reef or in basins, any free-living animals attack them, though 

 I have expressly placed various species together in glass beakers for this purpose. 



"I would suggest that the pigment is respiratory. It is, I believe, quite true for each 

 species. Under any rock mass it is common to find many Tunicate colonies of one species, 

 and one species only. This may be white, red, pink, blue, or purple, yet the Turbellaria 

 did not appear to me to differ in colour under different masses of rocks." 



In conclusion, my thanks are due to Mr Stanley Gardiner for giving me the opportunity of 

 undertaking this work, and to Dr Gamble for much assistance with regard to literature. To 

 both these gentlemen I am indebted for useful advice and suggestions. I have also to thank 

 Professor Hickson, both for penuission to carry out ray examination of this collection in the 

 Zoological Laboratory at Owens College and for the kind interest he has displayed in the work. 



III. LITERATURE. 



1. Benham. Treatise on Zoology, Pt. IV. 1901. 



2. Bergendal. Kongl. Fysiogr. Sallskapet ; Lund Handlingar Ny Foljd. 1892 — 93, Bd. 4. 



3. Rev. Biol. Nord France, v. pp. 257—366. 



4. CoLLiNGWOOD. Trails. Linn. Sac. Lond. ii. (Zool.) i. 1875. 



5. Gamble. Q.J. M.S. xxxiv. p. 433 (1893). 



6. Graff, v. Zeitschr. wiss. Zool. LV. 1893, p. 189. 



7. Mitth. naturwiss. Ver. filr Steiermark, Jahr 1889. 



8. IJIMA. Zeitschr. wiss. Zool. xi. (1884), p. 359. 



9. Lang. Naples Monogr. xi. 1884. 



10. Plehn, von. Jena Zeitschr. xxx. p. 137, T. viii — xiii. 



11. Ergehn. Plankt.-Exp. Heft i. (1896). 



12. Jena Zeitschr. xxxi. p. 90, T. v. (1898). 



13. Zool. Jahr. Syst. xii. p. 448—452, 2 figs. (1899). 



14. Stummek-Traunfels, von. Zeitschr. wiss. Zool. Lx. p. 688, T. xxxv — xxxviii. 



15. Verrill. Trans. Connect. Acad. viii. pp. 459 — 520. 



16. Wheeler. Am. Journ. Morph. ix. p. 167 (1894). 



17. WiLLEY. Q.J. M.S. xxxix. pp. 323—342. 



18. Q. J. M. S. XL pp. 293—205. 



19. WOODWORTH. Bull. Mus. Harvard, xXL p. 1 (1891). 



20. Bull. Mas. Harvard, xxxn. pp. 63—67 (1897). 



