54 ON THE STRUCTURE OF NOCTILUCA MILIARIS. 



the sides of this process to be surrounded by fusiform trans- 

 versely-striated fibres or folds, I could not determine which. 



Krohn states that he repeatedly saw the eyesta voided ' in 

 the neighbourhood of the groove of the body,' but he could 

 not determine at what exact point, and he inclines to think it 

 must have taken place tlirough the mouth. 



I am equally unable to bring forward direct evidence on 

 this point, and my belief in the existence of a distinct anus is 

 founded simply on the structural appearances. 



In front of and above the gastric cavity is the nucleus (c), 

 described by Verhaeghe and Krohn. This is a strongly re- 

 fracting, oval body of about l-460th inch in length, which, 

 by the action of acetic acid, assumes the appearance of a 

 hollow vesicle. The anterior radiating fibres pass from it ; 

 the posterior from the alimentary canal. 



Quatrefages anil Krohn consider that a process of fissiparous 

 multiplication takes place in Noctiluca ; both of these ob- 

 servers liaving found double individuals, thouyh very rarely. 

 According to the latter writer, division of the body is pre- 

 ceded by that of the nucleus. 1 have not had the good fortune 

 to meet with any of these forms, and the only indication of a 

 possible reproductive apparatus which I have seen consisted 

 of a number of granular, vesicular bodies (fig. 5 A), of about 

 l-2000tli inch in diameter, scattered over the surface of the 

 anterior and inferior part of the body. 



Such is what repeated examination leads me to believe is 

 the structure of Noctiluca; but if the preceding account be 

 correct it is obvious that the animal is no Rhizopod, but must 

 be promoted from the lowest ranks of the Protozoa to the 

 highest. 



The existence of a dental armature and of a distinct anal 

 aperture, are structural peculiarities which greatly increase 

 the affinity to such forms as Colpoda and Paramccciuvi, indi- 

 cated by Krohn. Noctiluca might be regarded as a gigantic 

 Infusorium with tlie grooved body of Colpoda, the long pro- 

 cess of Trachelius, and the dental armature 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 con- 

 stitution of at least a distinct family for this singular creature. 



Economy oJ Closterium Lunula. By the Hon. and Rev. 

 S. G. Osborne. Communicated by Jabez Hogg, Esq. 



Thi: division of labour-principle holds as good amongst 

 microscopibts as amongst any other workers in the fields of 



