XX.— N OTES ON PHOSPHORESCENCE IN 

 MARINE A N I j\I A L S . 



By R. E. Lloyd, M.B., B.Sc, Captain, IMS., Surgeon Naturalist, 

 Marine Survey of India, 



WITH 



A DESCRIPTION OF A NEW POLYCH^TE WORM. 

 By A. WiLLEY, D.Sc, F.R.S., Director, Colombo Museum. 



Towards the end of 1905, the R.I.M. Surve}^ Ship " Investi- 

 gator " trawled five times in the shallow waters of the northern 

 part of the Persian Gulf. On one of these occasions the trawl was 

 lowered late in the afternoon, so that the process of preserving 

 the specimens had to be carried out in the dusk of the evening. 

 While depositing some of them in formalin, m}'' attention was 

 arrested by a fine display of illumination by one of them, — a 

 certain active Pol3^chsete. 



Before dropping this worm into the solution, no phosphores- 

 cence was noticed, but under the stimulus of the irritant, two 

 rows of brilliant points of light, one on either side of the animal's 

 back, became visible, and remained so for several seconds before 

 graduall}^ fading away. 



These points of light were circular in outline, and about the 

 size of a small pin's head. It was noticed that they were separated 

 by equal intervals, that they appeared less in number than the 

 segments, that they were situated about the bases of the para- 

 podia, and that they were very prominent. 



The worm was soon identified as probably belonging to the 

 genus Lepidasthenia , and was sent to Dr. Willey, of Colombo, 

 who confirmed it in this genus, pronounced it without hesitation 

 as a new and well-marked species, and kindly gave the description 

 quoted verbatim at the end of this paper as the definition of the 

 species. 



In sending this definition Dr. Willey asked me to add my own 

 observations and figures, and further remarked that the first pair 

 of elytra required a special description. The first pair of elytra 

 are about three times the size of the others, they are carried on 

 peduncles which curve forwards and then inwards, so that the 

 elytra of either side overlap, mid-dorsally, hiding the prostomium 

 and the bases of the palps and antennae. It will be noticed in fig. i, 



