212 Part ITI —Twenty-fifth Annual Report 
and moderately stout terminal appendages, one of which forms a short 
hook-like process, while the other is straight and terminates in two 
slender setz of unequal length (fig. 12). 
The structure of the fourth pair appears to be similar in the two sexes ; 
the outer branch is moderately slender and elongated, and composed of 
three sub-equal joints armed with long spiniform setz on the outer 
margin ; the inner branch is very short and two-jointed, the first joint 
being extremely small, while the second is slender and moderately 
elongated, and furnished with three small terminal setz (fig. 13). 
The fifth pair in the female consists of a small basal joint to which is 
articulated a narrow elongated plate about four times longer than broad, 
and provided with a number of setz arranged as shown in the drawing 
(fig. 14). In the male the fifth pair is similar to those of the female, but 
smaller and less spiniferous (fig. 15). 
The furcal joints in both the male and female are elongated and 
slender and set widely apart; they are each furnished with a long and 
stiff apical bristle and a few small hairs (see fig. 6). 
I have obtained this species in the same situations with the Harrietella 
previously mentioned, but it seems to be a rarer form, and males 
especially appear to be very scarce. 
Notodelphyoida, G. O. Sars. 
Fam. Doropygide. 
Genus Votopterophorus, Costa. 
Notopterophorus papilio, Hesse. PI. xiv., figs. 1-19. 
1865. Notopterophorus papilio, Hesse, Observations sur des 
Crustacés rares ou nouveaux des cdtes de France, Ann. des 
Sct. Nat., 5th Sér. zool., vol. i., p. 338, pl. xi., figs. 1-13. 
1878. Notopterophorus papilio, G. 8. Brady. A Monograph of 
the Free and Semi-parasitic Copepoda of the British Islands 
(The Ray Society), vol. i., p. 142, pl. xxxi., figs. 3-12. 
The Entomostracan to which M. Hesse has given the name mentioned 
above is one of the most remarkable among a strange group of species 
found living as ‘‘unbidden guests” within the branchial chamber and 
sometimes in the alimentary canal of various simple and compound 
Ascidians. 
The distinguishing characteristic of Votopterophorus is, as the name 
implies, the peculiar wing-like appendages of the cephalo-thorax, which 
give to the creature its somewhat grotesque appearance. These append- 
ages, which are situated on the dorsal aspect, appear to be six in number, 
and assume the form of very thin and almost transparent plates, each of 
which terminates in long, slender, whip-like filaments. The frontal 
plate, which is obscurely triangular, has a hood-like structure, and 
appears to be furnished with three filaments—one central and one at 
each of the lateral extremities ; this plate seems to be an expansion of 
the first thoracic segment. The next four plates occur in pairs; the 
first pair spring from the second segment of the thorax, and the followiag 
pair from the third segment, and each single plate bears two whip-like 
filaments. The posterior plate, which is of one piece, moderately large 
and broadly triangular, and which springs from near the distal end 
of the last segment of the thorax, is apparently provided 
