Mr. Patterson on the Cydippe Pomiformis. 105 



Dr. Grant, in speaking of the nervous system of C. Pileus, states, that he 

 could perceive, at a short distance above the mouth, " a double transverse fila- 

 ment of a milky white colour, * * * * which formed a continuous circle round 

 the body. In the middle of the space, however, between each of the bands of 

 cilia, these cords presented a small knot or ganglion, so that there were eight 

 ganglia in the course of this ring." Never having been able to observe these 

 cords and ganglia in the C. Pomiformis, I took a number of specimens, some 

 living and others recently dead, and placed them under the microscope already 

 mentioned. But although Dr. Drummond, whose eye was well accustomed to 

 microscopic examination, gave his valuable assistance, we were unsuccessful in 

 detecting their presence. 



A transparent membrane extends across a portion of the lower extremity of 

 the body. It is entirely superficial, and may, perhaps, be of use in giving greater 

 strength and stability to that part of the animal. This, however, is merely a 

 conjecture, which I am at present unable to confirm or to correct by the opinion 

 of others, as the membrane does not appear to have been noticed by any previous 

 observer. 



The Beroe is most usually described as swimming with its mouth downwards. 

 Thus Blainville informs us, "II nage peu obliquement, I'anus ou I'extremite 

 arrondie en haut, et trainant ses deux longs cirrhes comme deux queues."* 

 Audouin and Milne Edwards, in like manner, state, " II existe dans I'axe des 

 Beroes une cavite qui va d'un pole a I'autre, et qui communique au-dehors a 

 I'aide d'une ouverture Inferieure, qu'on pent considerer comme I'avant bouche."f 

 The words of Lesson convey a very different idea i " Dans I'eau leur position est 

 tres oblique ou presque horizontale."J It is with the mouth downwards that the 

 C. Pileus is figured by Dr. Grant, and his description consequently bears refe- 

 rence to the animal as seen in that position. In this particular the C. Pomiformis 

 is the reverse of its congener, the usual position of the mouth being uppermost, 

 except when the animal is in a state of exhaustion, when it either rests on its 

 mouth, or lies languidly on its side, at the bottom of the glass. At other times, 

 when fresh and vigorous, its movements are lively, animated, varied, and inces- 



* Manuel, p. 130. 



f Quoted by Lesson, Annates des Sciences, tome v. p. 240. 

 % Annates des Sciences, tome v. p. 237. 

 VOL. XIX. J> 



