.. Fig. 4. 
362 DR. W. B. CARPENTER ON TOMOPTERIS ONISCIFORMIS. » 
with observers of unquestionable competency. And if, as would seem, scarcely to admit . 
of doubt, the process of sexual generation is carried on in the portion which I imagined 
to be larval, such a notion of its character becomes obviously untenable. I have deemed 
it right, however; to record my first impression, that any observers to whom the animal: : 
may present itself may have their attention more strongly directed to the peculiarities of. 
structure by which it was suggested. And as the animal does not seem to be very uncom- 
mon on our coasts (having been taken by the late Dr. Robert Ball in the Bay of Dublin, 
and by Dr. 8. J. Salter in Poole Harbour, as well as by Mr. Gosse and myself), it may be 
hoped that further light may ere long be thrown upon this question, as well as upon the - 
nature and distribution of the nervous system of this beautiful and interesting creature. - 
[SUPPLEMENTAL Nore.—Subsequently to the reading of the foregoing paper, another 
memoir on Tomopteris has been published in Miller's Archiv, 1858, p. 588, by Drs. 
Leuckart and Pagenstecher. These observers describe, under the name of Tomopteris 
onisciforinis, a. specimen with twelve pairs of fin feet and a caudal prolongation destitute 
of appendages, corresponding closely in its grade of development with a specimen I have 
mentioned in p.354. In the perivisceral cavity of the anterior part of -its body, they 
distinguished sexual products, as Busch and Huxley had done. They also describe, under 
the name of Tomopteris quadricornis, a smaller specimen, having only ten pairs of fin feet, 
and obviously identical with those first seen by me; this they consider to be specifically 
distinguished from the preceding by the presence of two pairs of horn-like appendages, 
the T. onisciformis seeming to have but one. I have already mentioned, however, 
that the second pair really exists in the larger specimens as in the smaller (p: 354); 80 _ 
that there is no reason for regarding the two as otherwise than specifically identical, the ' 
difference in the number of fin feet being obviously a character of age merely.] : 
EXPLANATION OF THE PLATE. 
fas. LXE 
Fig. 1. Young specimen of Tomopteris with ten pairs of fin feet; enlarged 10 diameters; — ^ d 
Fig. 2. Head ‘and i anterior part of the body, as seen upon the dorsal aspect, enlarged 38 diameters + s 
: 4, bifid extremity of one of the fin feet. TAR of: ng GE M 
Fig. 3. The same, as seen upon the ventral surface. . d. SE . 
Front view of the head, showing the position of the two anterior pairs of cephalic appendages, and bs 
TE the opening of the mouth upon the ventral surface. . EG UT 
Fig. 5. Caudal ‘extremity, showing the last two pairs of least-developed fin feet, and the termination of - = 
the intestine in an anal orifice; io 
Fig. 6. 
ed Advanced specimen of Tomopteris with sixteen pairs of fin feet; enlarged 10 diameters. 
sn extremity of the body of the specimen represented in fig: 6, with its last four pairs. å 1 
ordinary fin feet, giving origin to à caudal prolongation of very: différent conformation, furnis THE 
with eight pairs of rudimentary appendages. ipto dg 
Fig 8. Specimen of Tomopteris with thirty-three pairs of ebene XERaréy). 
Fig. 9. Masses of ova in the perivisceral cavity of the preceding (Huzley). 
