IDALIA ASPERSA. 



The little animal spawned while in confinement. The spawn is of a rosy hue, and has 

 the character of that of a Doris. It is about twice coiled, and forms a moderately deep, 

 elegant cup, a little more than a quarter of an inch wide. The ova are small, numerous, and 

 much crowded. We have twice before met with the same spawn on corallines from deep 

 water brought in by the fishing boats. At Newbiggin it occurred in June. Our individual 

 spawned in October. 



The shape of this Idalia varies much at different times. Sometimes it draws itself up 

 into a conical form ; at other times it spreads itself out into a flattish disc ; but usually the 

 back is much elevated, especially towards the oval area formed by the slight ridge which 

 includes the tentacles in front and the branchiae behind. Under the microscope cilia were 

 detected on the branchiae and tentacles, but nowhere else. The skin was observed to contain 

 spicula of a peculiar character. They are rather stout, pointed at the ends, and bent in the 

 centre where there is a circle of largish nodules ; there are also a few more imperfect circles 

 of small nodules towards the ends. The spicula are not numerous, and are placed without 

 any apparent order. 



The species of Idalia approaching most nearly to this are, I. lacunosa of Philippi, and 

 /. {Doris) quadricornis of Montagu, but both of these have only two tentacular appendages. 

 I. cirrigera, Phil, appears to have four, but it differs from this species in many respects. 



Tig. 1, 2, 3. Idalia aspersa, different views. 



4, 5. Front and side of a branchial plume. 



6, 7. Back and front view of a dorsal tentacle. 



8. Spicula. 



9. Spawn. 



10. A portion of the same more highly magnified. 



