25 



Chirodota Lsevis, and are arranged in groups. In the C. Myrio- 

 Irochus they are imbedded in myriads, as the name implies. 



Mr. Rossiter exhibited a living specimen of the .^cistes 

 Janus from the pond on the top of St. Thomas's Hill, agreeing 

 closely with the specimen figured in the Journal of the Royal 

 Microscopical Society for February, 1881, obtained from Loch 

 Lundie, and discovered by Mr. ]. Hood of Dundee. The 

 i^.cistes Janus is a most striking addition to the Melicertidse, 

 forming a connecting link between the two genera .^cistes and 

 Meliccrta. 



APRIL. 



Mj'. Sihert Saiuiclers on Barnacles. 



Mr. Saunders said that everyone who visited the seaside 

 could become familiar with representatives of the Cirripedia, 

 which so profusely cover stones, shells or woodwork left un- 

 covered by the receding tide. These stalkless barnacles, or 

 acorn-shells belong to the genus Balanus, of which there are 

 many species. The Lepadidse, or pedunculated Cirripedes, 

 formed another important family, one species of which, known 

 as the Goose Barnacle (Lepas anatifera), was formerly the sub- 

 ject of a curious fable. It was gravely asserted that it grew on 

 a tree by the water side, and that living aquatic birds issued 

 from it. Though the general outward appearance of these 

 species is quite different, the structure of the contained animal 

 is very similar. The Cirripedia occupy debateable ground 

 between the Crustacea and the Mollusca. Many naturalists have 

 associated them with the latter class, but it is now generally 

 admitted that their proper place is with the Crustacea. Darwin 

 ranks them as one of the main divisions of that class, and, 

 tracing them through all stages of growth, shows that segments 

 wanting in the mature animal exist in the larval stages. (Mr. 

 Saunders showed under the microscope living specimens of the 

 larva.) 



Taking one of the stalked barnacles from which half the 

 shelly covering had been removed, the included animal could be 

 better examined. The whole shell with the peduncle consists 

 of the first three segments of the head, firmly cemented to some 

 substance, and modified into a carapace which encloses the 

 mouth and the rest of the body. This, in reality the thorax, 

 consists of two portions ; one, a soft bag, called the prosoma, 

 carr)'ing the mouth and first pair of cirri ; the other supporting 

 the five pairs of posterior cirri, answering to the ambulatory 

 legs of the higher Crustacea. These are biramous, and are so 



