Microscopical Essays. 



417 



cal portion was cut lengthways ;' on obferving thefe parts, not 

 only the hole t of communication, Fig. 17, Plate XXIV. B, was 

 diftinclly feen, but one might fee through the end o of the young 

 one. On changing the fituation of thefe two pieces of prepared 

 polypi, and looking through the opening e, Fig. 18, the day- 

 light was feen through the hole of communication i. 



This communication between the parent polype and it's young 

 ones, may be feen on feeding them ; for after the parent, 

 a b, Fig. 22, Plate XXIV. B, has eaten, the body of the young 

 ones fwell, being filled with the aliments as if they themfelves had 

 been eating. In the hydra fufca the young ones do not proceed 

 from the tail part b c, Fig. 16, Plate XXIII. B, but only from the 

 part ac, with this exception, there is no particular part of the 

 body before the reft, on which they produce their young. Some 

 of them have been fo clofely obferved, and have fo greatly mul- 

 tiplied, that there would be fcarce any impropriety in faying they 

 produced their young ones from all the exterior parts of the 

 body. A polype puts forth often five or fix young ones at the 

 fame time. Mr. Trembley has had fome that have produced nine 

 or ten at the fame time, and when one dropped off another came 

 in it's place. 



Though Mr. Trembley had for two years thoufands of them 

 under his eye, and confidered them with the moll fcrupulous at- 

 tention, he never obferved any thing like copulation. To be 

 more certain on this head, he took two young ones the inftant 

 they came from their parent, and placed them in feparate glaffes ; 

 they both multiplied, not only themfelves, but their offspring, 

 which were feparated and watched in the fame manner to the 



3 E feventh 



