POLYCILETA OF THE L.M.B.C. DISTEICT. 251 



while the rest are shortened. When freed from the 

 investing mass of the cocoon, this trochosphere moves 

 through the water with a rotary motion, the long cilium 

 of the anterior tuft conspicuously directed stiffly forwards, 

 and apparently forming a larval sense organ. The most 

 advanced embryos showed a decided lengthening of the 

 body, chiefly of the post-oral part, and the beginning of a 

 constriction a little behind the mouth. 



Last year I observed these egg-masses of Arenicola 

 about the middle of March, on the Egremont shore; April 

 4th, at Port Erin, I.O.M., and April 24th, at Hilbre 

 Island. Mr. Sinel, of Jersey, has also sent me specimens 

 gathered in that Island on February 29th. This year, on 

 April 11th, I found large numbers of the usual bright 

 green hue in sandy pools among the sandstone rocks of 

 Hilbre Island associated with numerous castings. I noted 

 on the last mentioned occasion and also in the Isle of Man, 

 that no cocoons were to be seen on the exposed sandy 

 flats, though castings innumerable were there, and in the 

 pools where they were abundant were masses of Ulva 

 and of Enteromorpha to which the cocoons assimilated 

 exactly in colour. On the other hand, the cocoons of 

 Scoloplos were frequently to be noticed anchored among 

 the bare ripple-furrows of the sand expanses. Now these 

 egg-masses of Scoloplos are hardly to be distinguished in 

 colour from the muddy sands, the surface of the cocoons 

 becoming so coated with mud that the brownish contents 

 —themselves only a little darker than the sands— do not 

 show through. 



Family. — MALDANiDiE . 



*Nicomache lumbricalis, (Fabr.). 



Hab: 10. 



Three of the hindmost segments together with the 

 characteristic equally lobed anal funnel, were dredged off 



