175 



PRELIMINARY NOTE ON THE GENITALIA OF 

 ACANTHINULA LAMELLATA Jeff. 



By a. E. boycott. 



(Read before the Society, December 8th, 1915). 



Some time since Mr. J. W. Taylor drew my attention to the fact that 

 the anatomy and relationships of A. laviellata were obscure and 

 suggested that further investigation was desirable. With his help and 

 through the great kindness of Messrs. J. A. Hargreaves and R. A. Phillips 

 I have had a pretty free supply of material which has yielded such 

 curious results that I desire to bring them before the Society for 

 consideration without feeling altogether confident that they represent 

 the whole truth about the genitalia of laniellata. 



The specimens examined have been derived from three lots collected 

 in Yedmandale, near Scarborough, by Mr. Hargreaves, and from a 

 batch taken at Abbeyleix, Queen's County, by Mr. Phillips. Gross 

 dissection, with needles, under the microscope proving useless in my 

 clumsy hands, the enquiry has been based on the examination of 

 serial microscopical sections of the animals fixed in a more or less 



extended position after the shell had been chipped off. Such sections 

 consist rather largely of pieces of small tubes, often without any local 

 connections to hold them in position. The possibility of these bits 

 falling out of the sections has been controlled by the examination of 

 specimens cut in situ in the decalcified shell and by using a most 

 convenient method of double embedding in clove-oil-celloidin and 

 paraffin communicated to me by Mr. A. Bacot, RE.S. 



The genitalia so shown prove to be of a singularly simple form. 

 There is the usual hermaphrodite gland; from this leads a well- 

 formed hermaphrodite duct which on reaching the albumen gland is 

 bent on itself. There succeeds a simple form of oviduct, with many 

 mucous cells in the wall but without the voluminous glandular mantle 



