20 



THE CTENOPHORA 



FAMILY 1. MERTENSIDAE. The body compressed in the sagittal 

 plane. Sub-transverse costae longer than the sub-sagittal. SUB-FAMILY 1. 

 MERTENSINAE. The aboral pole devoid of processes. Genera Euchlora, 

 Chun ; Charistephane, Chun. SUB-FAMILY 2. CALLIANIRINAE. Body 

 produced at the aboral pole to form two or four processes, into which the 

 aboral ends of the meridional canals extend. Genera Callianira, Peron, 

 with two processes ; Lophoctenia, Bourne ( = Beroe, Mertens), 1 with four 

 processes. FAMILY 2. PLEUROBRACHIIDAE. Body circular in section, 

 Costae of equal length. Genera Pleurobrachia, Fleming ; HormipJiora. 

 L. Agassiz ; Lampetia, Chun ; Euplokamis, Chun. 



ORDER 2. Lobata. 



Body compressed in the transverse plane. The sagittal areas of the 

 body produced to form two more or less extensive peristomial lobes. 

 The ends of the sub - transverse costue produced into four lappets or 



CSS. 



CSS. 



Fm. VIII. 



Devmen katoktenota, Chun, from the transverse aspect, m, mouth ; st, stomodaeum ; i, 

 infundibulum ; ess, sub-sagittal costae ; ctr, sub-transverse costae ; an, auricles ; tt, accessory 

 tentacles ; lc, serpentiform lobular canals ; zz, joints where the lobular canals communicate 

 with the sub-transverse, meridional canals ; pp, papillae. 



auricles on which the combs extend. The eight ciliated grooves are con- 

 tinued over the whole length of the costae. Sub-sagittal costae longer 

 than the sub-transverse. Transverse gastrovascular canals obsolete, a pair 

 of canals being given off from either side of the infundibulum. Meridional 

 and stomodreal canals communicate with one another by means of prolonga- 

 tions of the latter, and from these connecting vessels serpentiform diver- 

 ticula are given off into the sagittal lobes. Tentacular sheaths absent. 

 Tentacles in the form of numerous accessory filaments situated in grooves 

 which extend from the mouth to the bases of the auricles. 



FAMILY 1. LESUEURIDAE. The sagittal lobes rudimentary; auricles 

 long and ribbon-like. Genus Lesueuria, M. Edwards. FAMILY 2. 



1 The four-crested Callianirid, to which I have given the name Lophoctenia, was 

 discovered by Mertens in 1833, and was named by him Beroe. As this generic name 

 belongs to another form it cannot he retained, and since no other has been suggested 

 I have renamed Merteus's form Lophoctenia (\60os, a crest, and /trelr, a comb). 



