172 DR. BAIED ON THE APHRODITACEAN AJSTlSrELIDES. 



It refers to the employment of various-sized watch-glasses. They 

 are affixed to the vertical sheets of mica, and the specimens 

 are introduced into their concavities ; each glass being fastened 

 to the mica by threads passed through two or more holes pre- 

 viously drilled at its circumferential margin. I find two holes 

 sufficient, one on either side ; but greater fixity and security may 

 be obtained by boring more apertures at equidistant intervals. 

 This adds, however, to the expense and risk of breakage. The 

 holes should freely admit the passage of an ordinary needle. This 

 plan is eminently suitable for the display of small flukes, Cysti- 

 cerci (of the "measle" kind), and minute Hydatids. 



5. A few years ago I initiated the employment of carmine, 

 aniline, and other pigments in the preparation of Entozoa for 

 museum purposes, and I am glad to be able to state that ^the 

 specimens thus first treated still retain their colouring almost 

 unimpaired ; at least, this is the case with those saturated with 

 carmine. Tor microscopic purposes, these pigments had long 

 previously being employed both here and on the Continent. 

 Some of the magenta-dyed preparations have stood very well, 

 where the carbolic-acid solution had been sufficiently strong to 

 fix the colour. The specimens preserved in the Museum of the 

 Middlesex Hospital, however, hardly offer a fair criterion of the 

 durability of this latter pigment, since the preparations have 

 been all along exposed to a strong sun-light. In a large collec- 

 tion the use of carmine should not be excessive, but in particular 

 instances (as, for example, in the encapsuled condition of Tri- 

 china spiralis) its employment cannot be too highly recommended. 



[The above remarks were illustrated by the exhibition of spe- 

 cimens of Hydatids, Cysticerci, Amphistomata, Spheerulariae, Tri- 

 chinse, Spiropterae, and Coenuri, prepared by the author for the 

 Museum of the Eoyal CoUege of Surgeons.] 



Contributions towards a Monograph of the Species of Annelides 

 belonging to the Aphroditacea, containing a List of the known 

 Species, and a Description of some new Species contained in 

 the National Collection of the British Museum. By W. Baikd, 



M.D. 



[Bead June 1, 1865.] 



"Animalium molluscorum in mari degentium vix centesimam partem 

 bene novimus. Tanta autem est Naturae in eorum forma et fabrica varietas, 

 et tanta non modo inter genus et genus, sed inter generum extremas 

 quoque species plerumque discrepantia, ut vel exercitatissimi in his ssepe 



