14 THE ROTIFEEA. 



A. HF.imicKi, de Gucrna (173, 175), (PI. XXXIII. fig. 5). SP. CH. " Body nmpliora- 

 shaped :. tropH stout, consisting only of two rami, with an almost straiglit internal 

 •margin, terminated by a strong hook, loith an apex not internally denticulated." Mr. 

 Herrick, who discovered this Asplanchna in Minnesota, U. S., says it resembles Bright- 

 tvellii and is hermaiihrodite. M. de Guerno {loc. cit.), while very properly discrediting 

 the latter statement, forms a new species of it solely on account of the shape of the 

 rami. As these, however, are of extraordinary shape and proportions, and have no 

 fulcrum or unci, I think it better to wait till there is some further account of the creature 

 published. 



A. GiBODi, de Gucrne (173), (PL XXXIII. fig. 6). SP. CH. "Body globose ; tropM 

 elongated, stout, consisting only of two rami, each with a bidentate apex, having one 

 tooth curved and sub-obtitse, the other compressed and lamellar." M. de Guerne says 

 these tropin are distinguished from all others by the lamellar teeth just below the apex. 

 But this is an error, for Brightwellii, priodonta, and Ebbesbornii have all these apparent 

 lamellar teeth. In fact their rami, seen side-mse (PI. XXXIII. fig. 2 b), are evidently 

 deep plates bounded at the top by a thick broad ridge ; which, at the apex, is prolonged, 

 beyond the plate, into a curved hook. When the ramus is subjected to pressure from 

 above, the deep plate is bent by the glass (to which it stands at right angles), and its 

 free lower corner is twisted, so as to look sometimes like a second tooth, just below the 

 extreme aj)ex, sometimes like a small plate : and often it is hidden altogether, under 

 the thick curved pincer-like ridge, which alone is usually drawn as the ramus. I was 

 unaware of this construction, till my attention was drawn to it by exactly reproducing 

 M. de Guerne's figure of the tropin of Girodi, on crushing the tropin of Brightivellii. 

 These latter are correctly drawn m fig. 4, PL XXXlII. Nor is this ah. The imci dis- 

 appeared entirely, as they have in the figure of Girodi, fig. G, and the lines a, a, seen in 

 that figure were shown to be the crushed remains of fibres {b, b, fig. 4), of the true 

 nature of which I am in doubt. 



There may be other characters which entitle Girodi to specific rank ; but the above 

 are evidently insufficient. 



A. Imhofi, da Guerne (173), (PL XXXIII. fig. 7). SP. CH. " Body ovately globose ; 

 trophi elongated, strong, composed only of two rami ; apex slightly incurved, bifid ; 

 ramus armed, in the middle, with a stout internal tooth ; base of the ramus triangular, 

 solid, with an external hook above." Here again the characters are taken almost solely 

 from the trophi ; which arc said, like those of Girodi, Herricki, and Krameri, to have 

 no mici : no other part of the structure is described, and neither the male, nor the ephip- 

 pial egg has been observed. Moreover there is an ambiguity in M. de Guerne's 

 description and drawing. What is meant by the " sohd, triangular bases of the rami " ? 

 They seem, according to fig. 7, to be bounded by the lines c, c ; which are of the same 

 depth of tint as the outer edges of the rami, and are contmuous with them. But these 

 lines arc really the boundaries of a soft muscular mass which embraces the narrow ful- 

 crum, /. The true bases of the rami are the curved lines, d, d. The same ambiguity 

 exists in the drawing of Girodi, fig. 6. That these sloping lines, c, c, are the edges of 

 muscle, and not of the hard parts of the jaws, is certain : for I have seen the fulcrum,/, 

 moved slowly to and fro, like a pendulum, by the alternate contraction and expansion 

 of the muscle on either side. 



A. Imhofi may very possibly be a new species ; but the rami, as drawn in M. de 

 Guerne's figure, are hardly enough to make it certain. 



A. Keamebi, de Guerne (173), (PL XXXIII. fig. 3). SP. CH. " Body globose : trophi 

 consisting only of two rami, tvhich are curved, slender at the base, stout at the extremity, 

 sickle- shaped, and with the interior margin denticulated:' It will be seen that here the 

 trophi, on which alone the creature's distinct specific rank is made to depend, have two 

 fulcra ; one to each ramus. If the drawing be correct, then, the thin deep plate, of which 



