REPRODUCTION OF BEROE. 97 



hours after this minute subdivision several of them 

 were vibrating as usual, and at the expiration of forty- 

 two hours the two cilia belonging to one fragment 

 showed undiminished activity. 



The mode of reproduction in the Beroes has long 

 been a subject of interesting inquiry, and on this 

 point of their history Dr. Strethill Wright had the 

 opportunity of making the following observations*. 

 He found in Morecambe Bay, near Lancaster, one 

 day in June, swarms of the Cydippe pomiformis. 

 Every little creek and channel in the sand-banks was 

 full of them, where a day or two before or afterwards 

 not one was to be seen. On examining one of these 

 animals confined in a jar of sea- water, a great number 

 of transparent vesicles were observed in the lateral 

 water-vascular canals. Some of these vesicles were 

 floating freely in the circulating fluid, but the greater 

 number were attached in pairs to the inner surface of 

 the muscular bands, a pair between every two of the 

 ciliary paddles. The constant motion of the paddles 

 rendered it difficult to ascertain the true nature of 

 these vesicles, but the next day a considerable num- 

 ber were seen floating freely in the jar, and were 

 placed under the microscope. They consisted of a 

 transparent and highly refractive vitellus, containing 

 a germinal vesicle and germinal spot, and surrounded, 

 at a considerable distance, by a thin envelope or shell. 

 Several of these ova were placed in a small trough of 

 sea-water and carefully watched for some days, but 

 no further development occurred in them. In the 

 meantime, the water containing the parent Cydippe 



* Edin. Phil. Journ. 1856. 



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