396 M. E. Grube on the Capitellse 



readied to the seventeenth, and the diameter of which was not 

 much greater than that of an ovum. 



D'Udekem*, in his "Classification," also speaks only of two 

 ovaries. In one of the specimens from Ostend, sent to me in 

 March by Van Beneden, I likewise found ova ; their diameter 

 was O05 line, and that of their germinal vesicle 0*0015 line. 

 Upon the organs secreting urine, which, according to d'Udekem, 

 are situated in almost all the segments of the body, I have made 

 no observations. 



The remarkable anchor-shaped Gregarina which Oersted dis- 

 covered in the intestine of his Capitellce have also been found by 

 Van Beneden, Leuckart, Claparede, and myself. Claparede's 

 figuref shows a completely developed form, in which the nucleus 

 is indicated merely by the pale spot in the foremost third of the 

 body. In younger animals, in which the body is not yet so 

 much filled with greenish mass, this nucleus appears far more 

 distinctly : it is sometimes nearly circular, sometimes oval, con- 

 tains a nucleolus, and is situated nearly always in the same spot, 

 but sometimes more anteriorly, between the bases of the arms of 

 the anchor. As the median body increases in length and be- 

 comes more slender, these arms also gradually grow out ; they 

 are at first very short, like two mere teeth, and extended hori- 

 zontally ; and in still younger states, where the length of the 

 body is still scarcely one-fourth of that of the mature animal, 

 no trace of them is to be seen, the form of the animal being then 

 a rhomb with rounded angles, much produced posteriorly. This 

 entire series of changes, of which I only saw a few, has been 

 observed by Oersted. 



The next question which presses upon me is, whether the 

 Capitellce observed in Copenhagen, and those found at Ostend, 

 on Heligoland, and on the Hebrides, belong t.o one and the 

 same species with the Lumbricus capitatus described by Fabricius. 

 The differences of size of sexually mature individuals are very 

 considerable : whilst Oersted states the length of his Lumbrico- 

 na'is marina at 10 or 12 lines, and I even had males of only 

 5 lines, Van Beneden found the males 24-27 lines and the 

 females as much as 4 inches, long ; Claparede sometimes found 

 them still longer, and Leuckart even met with specimens as 

 much as 7 inches in length. The indication of Fabricius — 

 " longitudine Lumbrici terrestris" — shows that, although, ac- 

 cording to his statement, the Greenland animals of this species 

 do not attain such large dimensions as the Norwegian (amongst 

 which he mentions one a foot in length), his specimens were 

 certainly of the larger kind. The Capitellce from Greenland 



* Memoires de l'Acacl. Roy. de Belgique, xxxi. 1859, p. 25. 



t Memoires de la Soc. de Phys. et d'Hist. Nat. de Geneve, pi. 1. fig. 15. 



