VoL. 2] Ritter—The Pelagic Twnicata. ' 98 
condition. The following table shows the length of the animal 
and the width of the muscle bands, and the state of the viscera, 
in seven specimens observed at the San Diego laboratory in June, 
1904: 
No. Lengh of Zooid. Width of Muscle. Condition of Intestirfe. 
UE etoeege eis Cb 2.22 mm. .20 mm. organs intact 
isi Aer roca ore 2.59 mm. .18 mm. organs far degenerated 
Big Sino came Gere 2.60 mim. .129 mm. organs intact 
Gh, Such Sa eRe eRe 2.77 mm. .148 mm. organs intact 
Descenscpecanec she pir2 3.33 mm. 27 mm. organs nearly gone 
\Digraoneiore A cman 4,25 mm. .o7 mm. organs wholly gone 
Ucediare Rieter atte 5.00 mm. oo mm. organs wholly gone 
While, owing to the difficulty in getting accurate measure- 
ments, and of expressing in precise terms the stage of degenera- 
tion of the organs, and probably, more than all, to individual 
variation, such data as this are not very significant, they show 
in a general way what is undoubtedly true; viz., that the degen- 
eration begins relatively late here, and then, that the increase in 
size of the zooid and width of the muscle bands go on pari passu 
with the rather gradual degeneration and resorption of the 
internal parts. 
A few remarks must be made concerning my position with 
reference to the status of D. ehrenbergii and the representatives of 
the four generations assigned to it. First, in regard to the name. 
I agree with the proposal of Borgert, 94, and the practice of 
Lahille, 90, that if such a species as ehrenbergui is to be recog- 
nized at all, it should be Uljanin’s, and not Krohn’s. Krohn, 
56, proposed this specific name for what he regarded as Quoy 
et Gainard’s D. denticulatum, on the wholly arbitrary and un- 
‘ 
permissable ground that Quoy et Gainard’s name was ‘‘unpas- 
send,’’ since other species as well as this are denticulated about 
the branchial orifice. Since no author, so far as I am aware, 
between Krohn and Uljanin applied the name gegenbaurvi either 
to D. denticulatum or to any form supposed to belong to this 
species, the real question is, Do all the forms assumed by Uljanin 
to belong to D. denticulatum, and hence ealled by him gegen- 
bauru, actually belong to one species, or was he in reality dealing 
with generations representing two species, one of which was 
denticulatum and the other an undescribed, or at least an un- 
