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tively short horns.” This specimen was from the same sun fish, 
so that there can be no reasonable doubt that it is of the same 
species as the long-horned specimen. To judge by the parallel 
case of Sphyrion laevigatum, these deeply-imbedded parasites 
vary greatly from specimen to specimen in the measurement of 
their imbedded parts. 
Dr. Wright in his description mentions an eye-spot, in which 
he could find no appearance of a corneal structure or of the 
three cornea-like portions described by Claus for a species of 
Pennella (Beobachtungen iiber Lernaeocera, Peniculus und 
Lernaea, 1868). He further mentions a pair of minute anten- 
nules, entennae obscurely three-jointed, with the “ distal joint 
cheliform,”’ and surrounding the oral opening a number of small 
cauliflower excrescences. The chelate second antennae are 
figured for their Pennella varians by Steenstrup and Litken, 
by Lubbock for the juvenile Baculus elongatus, and by Brady 
for the likewise juvenile Hessella cylindrica. 
In the specimen from Table Bay the head is not very large, 
globular, with a circular group of close-set tubercles round the 
mouth opening. The blunt arms are directed slightly back- 
wards, and are not much longer than the diameter of the head. 
On the “neck ”’ between the arms are the four pairs of micro- 
scopical pointed processes representing the limbs. Attached 
at the point where the pale imbedded part of the specimen 
meets the brownish purple free portion is a specimen of Con- 
choderma virgatum (Spengler), of which some juvenile examples 
are attached at the other extremity of the genital segment, 
adjacent to the ovigerous tubes. It is said that Pennella 
balaenopterae, Koren and Danielssen, attached to a Balae- 
noptera rostrata (Fabr.) on the coast of Norway was also found 
associated with this same Thyrostracan species (Zool. Record 
for 1877, Crustacea, p. 34). The pale “neck” near the centre 
has four or five more or less joint-like constrictions. The dark 
part is rugose with close-set circular ridges, which are in part 
finely tuberculate. The ovigerous sacs were broken. 
The resemblance which the free part of this copepod bears 
to a sea-feather is quite striking enough to explain its inclusion 
by Linnaeus in the genus Pennatula. Probably there are very 
few marine animals that care to feed on Alcyonarians compared 
with the number to which crustaceans are palatable. It may 
therefore be presumed that the resemblance of the Pennella’s 
exposed part to a Pennatula is protective, and that the attached 
barnacles also profit indirectly by a disguise which was at least 
artful enough to deceive Linnaeus. 

[PUBLISHED 20TH FEBRUARY, 1905. | 
