184 CTENOPIIORiE. Part II. 



As to the (limonsioiis of Cestiun, Vogt calls uiiltli what is truly the height 

 of the animal ; LeSueur, Cuvier, Blaiiiville, Mertens, and Gegenbaur ai»ply the 

 same designation of width to the surfice which has the longest diameter, and 

 which Vogt correctly calls length ; the transverse diameter, or that which measures 

 the thickness of the tape-like body, being the shortest diameter. A comi)arison 

 witli Pleurobrachia or Bolina, taking the relative positions of the actinal and 

 abactinal poles and of the interambulacral tulles into consideration, will at once 

 set tills matter right. But it is obvious that this genus reijuires reexamination 

 Avith reference to the general course of its chymiferous tubes and the number of 

 rows of its locomotive flappers. I have no doubt that the chymiferous tubes which 

 follow the rows of locomotive flappers on Ijoth sides of the elongated aljactinal 

 pole are the two anterior and the two posterior amlndacral tubes, and those which 

 Eschscholtz has described as median tubes, the four lateral ambulacra! tubes; but it 

 remains to l)e ascertained whether these tulx's are entirely destitute of locomotive 

 flappers or not. From the figure of Eschscholtz, I suspect that each row of loco- 

 motive llaiiiiers may correspond to a. double row, as in young Cydippida\ If this 

 should be the case, Cestum would truly form a iburtli sub-order, characterized, in 

 addition to these structural peculiarities, by the trend of its tentacular sac, and the 

 extraordinary development of its anterior and posterior pairs of spheromeres. The 

 natatory ilappers of the actinal margins described and figured l)y Vogt are likely 

 to be homologous to the auricular fringes of the Mnemiidiv. 



As to Callianira. judging from the descriptions and figures thus fir published, 

 it would seem to Ijc but slightly different from Pleurol^rachia, and therefore' to 

 belong to the sul)-order of Cydippidaj ; but as no recent investigator had an 

 opportunity of examining any species of that genus since the structure of the 

 Ctenophoiu" has begun to ))e ) letter known, it is impossible to form a decided 

 opinion u[)on its affinities. I merely infer its Cydijipian relationship from the 

 position of tlie tentacles in Callianira triploptera. The most striking character 

 assigned to it consists in the wing-lilce projection of the rows of locomotive tlajipers, 

 of wliicli there are three pairs, according to the descriptions, though the figures 

 show tliat there must lie four jiairs. 



Thus far, I have designated the different suli-orders of the Ctenophonv by the 

 name of the liest-known family Ijelonging to each ; Imt as these names will have 

 to be retained tin- the families themselves, it is necessary now to select some others 

 for the suli-orders. For the Beroida' the name Eiin/sloiiuc, or Euri/slouKilii, apjilied 

 to them by Leuckart, may lie retained ; for the Cydiiipida I would 2>i'<'pose that 

 of /^accafcr, on account of the deep pouch in which the tentacular apparatus is 

 received ; and with Eschscholtz (Isis, ISlio, p. 741), that of Lohatu' for the Mne- 

 miidiv, on account of the lolie-like prolongation of the spherosome. Should Cestum 



