Field Notes. 



27 



about fifteen minutes. Its lontj- antennae were noticeable 

 tucked under its body, these being gfradually released from 

 between the body and the glass until they were fully stretched 

 in their natural position. Next the wings were freed, though 

 not unfolded ; they were of a light grey colour. When the 

 insect had got rid of its skin it remained almost motionless for 

 thirty minutes whilst its wings were drying. Then the long 

 slender wings were spread and a short flight taken. Short 

 flights and rests alternated for a couple of hours, then the 

 caddis fly finally left the vicinity of the aquarium. — (Mrs.) M. E. 

 Williamson, Headingley. 



l^OLLVSCA, 



Petricola pho/adiformis in Lincolnshire. — I was glad to 

 see the notes by Mr. C. S. Carter under the above heading in 

 your November issue, having myself found this species 

 stranded in thousands at Skegness early in the present year. 

 Although most were dead, many specimens were alive. The 

 Skegness examples are much larger than the specimen figured 

 in Woodward's Mollusca, where New York is given as the 

 home of this species. My largest measures 2^ ins. by ins. 

 I found Petricola again at Skegness alive on the shore only 

 yesterday (Nov. 8th). I have also taken it this year at Clee- 

 thcrpes, so perhaps we may include it in our Yorkshire fauna 

 ere long. I should like to know why it appears in the Concho- 

 logical Society's list as one of those species ' whose claims to 

 be regarded as British are very doubtful.' — W. Gyxgell, 

 Scarborough. 



Progress of Egg Development in Limnea stagnalis. — 



The following notes may be worthy of record : — 



July 31st, 1907, 6 p.m. — Egg sac deposited on side of 

 aquarium. Milky white in colour, 1^ inches in length. 



Aug. I St, 6 p.m. — Sac now transparent. Counted 86 eggs- 

 in sac, each one slightly overlapping its neighbours ; they 

 seem to be arranged in about 25 rows of three each, the sac 

 being a little wider in the middle than at the ends. Each egg 

 is shaped like a hen's, the embryo (a little brown dot) being at 

 the lower end. 



Aug. 9th. — Embryo has grown, but no change in colour. 



Aug. 17th. — The form of the snails can now be plainly seen, 

 the shell having a light brow^n colour, the snail being darker 

 in colour, and denser. 



1908 January i. 



