St. Andrews Marine Laboratory. 465 



naturalists to the Ctenopliores, though at least two species 

 have long been known as inhabitants of our seas, viz. Pleuro- 

 hrachia and the ordinary Beroe (termed Iclyia cucumis by 

 Dr. Merle Norman). The former is perhaps the most abun- 

 dant and ubiquitous Coelenterate in inshore waters in all stages 

 of growth and at all seasons of the year, from January to 

 December — not, as formerly pointed out, always near the sur- 

 face, but often for long periods in our changeable climate 

 towards the lower regions of the water. The latter again is 

 more characteristic of the warmer months of the year, from 

 July till September, and the adults are often in vast masses 

 at the surface, especially in such regions as the voes of Shet- 

 land and the Frith of Forth, though it is of course met with 

 almost everywhere round our coasts. 



In using the large mid-water net in St. Andrews Bay at a 

 depth of 3 fathoms on the 19th May this year considerable 

 numbers of a form agreeing with Lesueuria vitrea, M. -Ed- 

 wards, were found amongst hosts of Pleurobrachice and 

 Hydromedusse. They were recognized by their great trans- 

 lucency, powerful locomotive flappers, and characteristic 

 shape ; moreover, on further examination their extreme deli- 

 cacy was conspicuous ; indeed, they are the most fragile of a 

 fragile group, and yet at this time the specimens were not 

 large — only from | to H in. in long diameter. From this 

 period onward to September they presented themselves almost 

 daily in great abundance in the mid-water net, and throughout 

 the bay generally, so that it was as common to meet with 

 them as with Pleurohrachia. In respect to novelty they took 

 the place of Clione of the previous year. 



They varied in size from the period just mentioned onwards, 

 that is, both large and small forms were present throughout, 

 the maximum of 3^ in. or rather more being reached, how- 

 ever, on August 4th. The reproductive organs appeared to 

 attain maturity towards the end of June and in July. The 

 capsule of the ovum measured "016 in. and the ovum proper 

 •0083 in. in a specimen procured in the first week of July. 



The genus Lesueuria was established in 1841 by Milne- 

 Edwards in his description of the structure and functions of 

 certain zoophytes &c. from the shores of France, the name 

 being given in honour of the able fellow-worker of Peron 

 in the description of the forms procured during the well-known 

 voyage to the Australian seas. He had found this new 

 Ctenophore (2 centimetres long) in great abundance in the 

 Bay of Nice. The account * of Lesueuria, as given by the 

 distinguished French zoologist, corresponds generally with 



* Ann. des Sc. nat. 2^ S(5r. tome xvi. p. 199, pis. ii., iii., and iv. 

 Ann. dc Mag. N. Hist. Ser. 6. Vol. ii. 33 



