254 



CTENOPHORiE. 



Part II. 



Fig. 90. 



BOLINA ALATA, Ag. 



(Seen from above.) 

 Central black speck (eye-speck). — n^itf 

 Long rows of locomotive flappers. — c dgh 

 Short rows of locomotiTe flappers. — t r 

 Auricles. — 5 s Circumscribed area of the 

 abactinal end of the body. 



a living state ; for it is out of the question to examine tlieir forms out of the 

 water, as all parts then collapse, fall together, break to pieces, or dissolve into a 

 shapeless mass. And, although I acknowledge the great interest of the descrij^tions 

 published by travelling naturalists, making us acquainted with the extensive 

 diversity of types of these remarkable animals all over the world, satisfactory illus- 

 trations cannot be expected from any quarters, save those where able observers 

 have resided for a longer time. The accounts of the generic and specific characters 

 of most Medusa3 must therefore be considered as provisional, so long as they are 

 not revised under favorable circumstances. 



Viewed from the aljactinal side, with the lobes con- 

 tracted, Bolina appears very much like Pleiu'obrachia, as- 

 suming then the form of a slightly compressed sphere {Fit/. 

 90); and were it not lor the fact that the circumscribed 

 area runs in the longer diameter, while it is transverse 

 to it in Pleurobrachia (PI. IP F/</. 20), the identity would 

 be almost perfect. Seen from the actinal side, however 

 {Fiff. 91), even when the lobes are contracted, the differ- 

 ence from Pleurobrachia (PI. IP. Fir/. 21) is already marked, 



owing to the circumstance that the vertical rows of loco- 

 motive flappers do not extend uniformly from one extremity 

 of the animal to the other, the two ambulacra of the 

 anterior and posterior loljes being much longer than those 

 of the sides, which terminate at about half the height 

 of the body. 



Viewed from the aljactinal side with slightly opened 

 lobes, the diflerence between the longitudinal and the 

 transverse diameter is already more marked ; but the four lateral lobes, or auri- 

 cles, a2:)pear as appendages to the anterior and posterior lobes. However, as the 

 larger lobes expand more and more, the small lateral lobes appear detached from 

 them, and their real connection with the sides of the main body begins to be 

 noticeable ; and the greater length of the anterior and posterior ambulacra and the 

 shortness of the lateral ones are quite apparent. In proportion as the anterior and 

 posterior lobes are more and more stretched forward and backward, their edges as- 

 sume a more pointed form, similar to the horns of a crescent, or rather to the blade 

 of a tomahawk, and the Avhole body may be compared to two tomahawks in minia- 

 ture, placed head to head in opposite symmetrical directions, the four short lateral 

 appendages looking like two small sticks projecting like short handles through the 

 eyes of the two heads for an equal length on both sides. Seen from the actinal 

 side in the same development of all parts, the general outlines do not difler 



Bolina alata, Ag. 

 (Seen from below.) 

 '( Mouth. — rr Auricles. — tttt Prolonga- 

 tion of the long vertical chymiferous 

 tubes. — =; Anastomosis of these tubes. 



