LUCERN A RLE AND THE IE ALLIES. 69 



details in this place. Frequently, if not always, the spermatozoa escape ilirowjh 

 the op-mphnujina directly into the outer world,' a thing impossible in Lucernaria), 

 since the genitalia have no connection with the two out(>r layers. 



139. Tile diyltlform bodies {diijituU, ^| IIG) demand notice in this connection, not 

 so much from any functional relation which they possess, as from their homological 

 position when contrasted with the site of similar organs in the Strobiloida. It may 

 fairly be questioned whether their proxiinitij to the genitalia has any reference to 

 their functions in connection with those organs, or whether they are there merely 

 as the result of carrying out a certain architectural desigii. In some of tlic 

 Charybdeitla?, as we learn through a letter- from Fritz Muller, " The digitiform 

 bodies ... in Tamoya are completely separated from tlie genitalia, and are 

 to be found within the common atrium of the digestive chambers." This, we 

 observe, is particularly noticeable in Tamoi/a qnaJnimdua,'^ where the diijitiili lie 

 in semicircles directly opposite the partitions of the umbella, but completely within 

 the main central chamber. Their proximity to the genitalia is lessened considerably 

 when compared with the closer connection of those in tha true Strobiloida, but 

 their relative position, as regards the prime vertical and horizontal planes of the 

 body, and in reference to the genital organs and to the sides of the proboscis is 

 not altered in the least, the architectural plan remaining the same. Notwithstanding, 

 therefore, their apparent functional connection with the reproductive organs in 

 almost all those Acalephse which possess them, their true relations are evidently 

 with the prehensile organs of the exterior, and we have, consequently, described 

 them in that light, in a previous section (§ 15, p. 57). This does not affect their 

 topographical homologies in the least, but, if anything, serves to disconnect them 

 from that false estimate which gives more weight to anatomical structure and 

 functional identities, than to morphological and homological relations, in determin- 

 ing the classificatory alliances of AcalepluB. To describe the digitidi in connection 

 with the genikdia, solely because of their proximity to them, would be about as 

 reasonable as to include the hind legs of Marsupialia in the category of reproduc- 

 tive organs, because they happen to be the nearest appendages, and, in part, help 

 to support the maraupium. 



■ See Liiceriiaria the Ccenotype, etc., ut sup. 



' Dated "January 1, 1865, Desterro, Brazil." 



' Since Jliluc Edwards has corrected (see Lcronx Ph;/swl., vo]. iii, p. 56) hi.s mistake in re«^ard 

 to the chyniiferous canals of Charybdea, and has shown that wliat ho formerly considered as such 

 are the partitions of the umbella, and what once seemed to be solid intervening masses are broad 

 tube.s, or camera;, alternating with the partition.*, it becomes clear that the Tamoya haploncma of 

 P. Muller is a Charybdea, and the T.' quadrumana, F. Muller, remains the true representative type 

 of the genus Tamoya^ while the Gliiropsaimus, Agassiz, founded on this species, becomes a synonym. 



