1889.] MR. F. E. BEDDARD ON ^OLOSOMA TENEBRARUM. 55 



pi. 9. fig. 9), in many of which the pigment is collected into a 

 globule lying in the middle of the cell ; this globule is, according to 

 Moseiey ("On Stylochus pelagicus, &c.," Quart. Jouru. Micr. Sci. 

 vol. xvii. 1877, p. 30), of a fatty nature, which is a further point of 

 similarity to ^olosoma. 



A resemblance — perhaps of greater importance — is shown to 

 Otenodrilus ; this genus consists of three species, in all of which 

 the integument is dotted over with coloured spots. In Ctenodrilus 

 monostylos (v. Zeppelin, " Ueber den Bau und die Theilungs- 

 vorgange des Ctenodrilus monostylos," Zeitschr. wiss. Zool. Bd. xxxix. 

 p. 617) and in Ct.pai-dalis(y. Kennel, "Ueber Ctenodrilus pcirdalis," 

 Arbeit. Zool. Inst. Wiirzburg, Bd. v. 1882, p. 375) these spots 

 are dark green. In the third species, Ct. parvulus, Dr. Scharff 

 (" On Ctenodrilus parvulus," Quart. Journ. Micr. Sci. vol. xxvii. 

 1887, p. 592) states that the spots are dark green or violet, and 

 that the colouring-matter is carried by an oily substance. I am not 

 quite clear from Dr. Scharff's paper whether he means to say that 

 the colour of these spots in Ctenodrilus parvulus is violet, or whether 

 green and violet spots both occur. In any case, the alternation of 

 green and violet is most suggestive in the light of what has been 

 already said regarding the change of the green pigment of ^olosoma 

 tenehrarum into violet by an alkali : moreover. Prof. Hartog informs 

 me that he observed " claret-coloured " spots as well as green in one 

 individual of JE. varie'iatum ; this fact is evidently of importance. 

 Moseley's observations upon the blue and red colouring-substances 

 of two land-planarians found at Sydney, N.S.W. (" On the Colour- 

 ing-matters," &c., loc. cit. p. II), suggest, however, the need for 

 caution in drawing such an inference ; he found that the blue 

 pigment of one of the worms was converted into red by the action of 

 acids, and surmised therefore that the red pigment of the other 

 species would prove to be identical with this pigment; but this 

 surmise proved to be incorrect. 



I have already suggested that the green pigment of ^olosoma 

 tenebrarum may be a respiratory pigment, capable of oxygenation and 

 deoxygenation ; the peculiar reaction with iodine which has been 

 referred to may possibly fit in with this hypothesis. I may also 

 mention that the change in colour of the cells from a bright yellow- 

 green to a dull olive-brown is very suggestive of a corresponding 

 taking up and giving off of oxygen, but I have no positive facts to 

 offer, and the proof is indeed extremely difficult. 



The blood of Molosoma tenebrarum is quite colourless at all times. 

 The plasma of the blood o? JEolosoma quaternariurn and ^. ehrenbergi 

 is stated by Vejdovsky {loc. cit. p. 18) to be colourless ; but he de- 

 scribes cells with branched processes attached to the walls of the 

 dorsal vessel in these species and in JS. tenebrarum, which contain a 

 yellow pigment. This may be haemoglobin, but there are no obser- 



far as I can remember). I made a few notes upon the worm, which I have un- 

 fortunately lost; I hope, however, to have an opportunity of finding the 

 Planarian again. It was not Vortex nor Mesostomum nor Convoluta. 



