ANNALS OF NATURAL HISTORY. 



XV. — On tvjo British Species o/Xydippe. By Edward 



Forbes, Esq. 



[With a Plate.] 



W HEN walking along the sandy shore at St. Andrews' on 

 Saturday the 28th of December, 1838, in company with my 

 friend Mr. J. Goodsir of Anstruther, our attention was di- 

 rected to a number of small, shining jelly-like globes which 

 were thrown up by the sea and rolled back on the receding of 

 the waves. On gathering some we were delighted to recognise 

 them as species of Beroe, and on placing the creatures in sea- 

 water were greatly astonished and pleased by their elegant 

 appearance and lively motions. They were kept alive for se- 

 veral days : imperfectly known as these animals are, the fol- 

 lowing remarks may prove of some importance in illustrating 

 their natural history. As every precaution was taken, and the 

 observations of several persons carefully compared, whilst 

 sketches were made at the time from the specimens (more 

 than twenty) collected, I trust they may prove deserving of 

 confidence. 



The animals found at St. Andrews 5 belonged to the genus 

 Cydippe of Eschscholtz, Pleurobrachia of Fleming : two dif- 

 ferent species occurred, the character and structure of which 

 I shall first describe. 



1st species — ciliferous ridges broad, commencing near the 

 anus and extending over two-thirds of the body ; rows of cilia 

 on each ridge 19 or 20, 3 to 7 cilia in each row; lateral fila- 

 ments very long. 



2nd species — ciliferous ridges narrow, extending over more 

 than two-thirds the length of the body from near the anus ; 

 rows of cilia about 36, crowded ; filaments moderate. 



Both the species are about the same size, seldom exceeding 

 three-fourths of an inch in length, though some specimens 



Ann. Nat. Hist. Vol.3. No. 16. May 1839. m 



