386 GENERAL HISTORY OF THE INFUSORIA. 



A " ^^ 2%' ^^ diameter. The common variety of form, with a constriction 

 of the circumference, which is noticed in free Noctilucce, and the radiating 

 filamentary branching striae beset with extremely minute granules in the 

 interior, were also characteristic of the encysted bodies, which 1 should be 

 more indisposed to separate from the Noctilucce, from their possessing the 

 most remarkable luminous power. At present we want the key to these re- 

 remarkable phenomena, as well as all knowledge of the development and 

 course of life of the Noctilucce.'' 



We have, in our prefatory observations on this family, alluded to the 

 opinion of the affinity of Noctilucicla with Ciliated Protozoa. Prof. Huxley 

 (op. cit. p. 54) has the following notes on this subject : — " If the preceding 

 account be correct, it is obvious that the animal is no Ehizopod, but must be 

 promoted from the lowest rank of the Protozoa to the highest. The exist- 

 ence of a dental armature and of a distinct anal aperture, are structural 

 peculiarities which greatly increase the affinity to such forms as Colpoda 

 and Paramecium, indicated by KJrohn. Noctiluca might be regarded as a 

 gigantic Infusorium with the grooved body of Colpocla, the long process of 

 Trachelius, and the dental armatui'e of Nassula united in one animal. 



" On the other hand, the general absence of cilia over the body, and the 

 wide differences in detail, would require the constitution of at least a distinct 

 family for this singular creature." 



To our apprehension there is no homology between the dental armature of 

 Noctiluca and of Nassula. In the latter, the so-called teeth appear to be 

 nothing more than hardened folds of the membranous tube of the oesophagus, 

 which may disappear by distension, — whilst in Noctiluca it is the condensed 

 uncinate margin of the oral cavity on one side which constitutes the dental 

 apparatus. Again, as to the presence of a distinct anal aperture, this cer- 

 tainly estabHshes no other affinity with the higher Ciliata than it does with 

 any other microscopic animalcules which possess such an outlet. On the 

 contrary, there is force in the particulars mentioned as opposed to their re- 

 lation with the Ciliata, viz. '' the general absence of cilia, and the wide differ- 

 ences in detail;" for cilia either diffused over the body, or collected into 

 groups to form a special ciliary organ, are, when taken in connexion with 

 the peculiar internal organization, so very characteristic that no microscopist, 

 unbiassed by imagination, would reckon Noctiluca among Cihata. In further 

 opposition to the notion of such an affinity, it may be urged that Noctiluca is 

 destitute of a ciliated contractile oesophagus, and of a contractile vesicle, 

 that it does not produce vacuoles in the introduction and transmission of food, 

 and that its so-called vacuoles appear to be actual closed sacs, separable from 

 the body. Other distinctive peculiarities between the two might be ad- 

 duced ; but we think that, on reflection and a comparison between them, ob- 

 servers will agree with us that Noctiluca is not a member of the Ciliated 

 Protozoa, that it cannot be included among them as a new family, but must 

 be placed in some other class of animalcules, or of itself form the representa- 

 tive of a new class. 



The Noctilucicla are inhabitants of the ocean, of the luminosity of which 

 they seem to be the most potent cause, of the many which have been 

 foimd in operation. They occur in the British seas, as well as elsewhere, 

 floating on the surface of the water. Mr. Byerly, of Liverpool, noticed 

 their prevalence in such numbers that the water acquired a rose-colour ; 

 and Dr. Webb (op. cit. p. 102) intimates that their luminosity must depend 

 on some pecuhar condition of their organs, or the media acting upon them. 

 This supposition is analogous to that made by Ehrenberg respecting the 

 phosphorescence of the Periclinicea, which he believed to be due to what he 



