1901.] AND YOUjNG OF A POLYCli.ETE AVORM, 7 L5 



In the month of May, 1809, I spent a fortnight at Ivan- 

 kesantarai, a small native town situated on the north coast five or 

 six miles west of Toudimanar. From here it was easy to reach 

 the lagoon at its southward entrance, and I naturally made 

 excursions thither, exploring the shallow waters on a native raft 

 or catamaran. Punting along in one of these, with the middav 

 sun blazing overhead and the water swirling up, hot and salt and 

 stinging to the ankles, between the logs of the raft, my attention 

 was caught by large numbers of little pear-shaped masses of jelly, 

 attached to the bottom by their narrow ends and swinging to and 

 fro \\ith the movements of the water. The native fishermen told 

 me that these were " the eggs of prawns," indicating a species of 

 Penceus which is common in the sea near the mouth of the lagoon, 

 and enters the latter at high tide, and of course no subsequent 

 demonstration was of the least avail to shake this belief, which is 

 entirely erroneous. Digging in the sandy bottom reveals the fact 

 that the objects in question are spawn-masses of a polychsete worm 

 of the genus Marplujsa^, which lies in its burrow- in the sand 

 head downwards and sets free its eggs. These, with the jelly in 

 which they are imbedded, pass upwards and form the pear-shaped 

 mass. 



The fully-formed spawn-mass (PL XXXIX. fig. 1) is about 

 four inches in length, of which more than one inch is due to the 

 stalk. It consists of a colourless translucent mucus, in A^hich 

 are imbedded small yellowish eggs, the whole being covered with 

 a delicate transparent pellicle. How this pellicle is formed I did 

 not discover, but would suggest that it is due to some change 

 undergone by the surface-layer of the mucus. When it is torn 

 the enclosed substance has a tendency to bulge out, as though it 

 were under a slight tension within (PI. XXXIX. fig. 2). The end 

 of the stalk, which is inserted into, and fills, the opening of the 

 burrow, contains a blackish or greenish mass of oval pellets, which 

 seem to be the dung of the worm. The mucus, Avhich is not 

 divided into areas corresponding to the eggs, appears structureless 

 under the microscope and contains numerous Infusorians. The 

 enclosed eggs and young are in various stages, the older ones being 

 generally on the outside and at the free end of the mass. 



' Owing to an unfortunate accident to a portion of luy uiaterial on the way 

 from Ceylon to England, only one damaged specimen of this worm is in my 

 possession. Dr. A. Willey lias kindly identified this for me as a species of 

 Marphysa allied to, or identical with, M. terefiuscula, Schmarda. Similar 

 spawn-masses are also found in the lagoon at Minikoi on the sand-flat at the 

 south end, in a spot where the conditions are not unlike those at Tondimanar 

 in some respects — namely, in that there is a shallow sheet of water, fully 

 exposed to the sun's rays, with a sandy bottom and with but a narrow opening 

 to the sea. A few spawn-masses were found ou a stretch of sand just outside 

 the bar of the Tondimanar lagoon, but I did not meet with them either at 

 Kankesanturai or on the south coast of Ceylon. 



^ This burrow, which extends to some distance in the sand, is perfectly 

 definite, but has not very strong walls. In it there are often to be found., 

 besides the Morphym, specimens of a small Nereid closely allied to Nereii< 

 hi-evicirris Grube, 1867. 



