the Copepod Family Ascomyzontide, 181 
Genus 9. ARTOTROGUS, Boeck, 1859. 
Important characters of the genus being problematic or 
entirely wanting in Boeck’s paper, it is impossible at present 
to draw up a diagnosis of Artotrogus; therefore I give here a 
critical abstract of the author’s description of the typical 
species. 
15. Artotrogus orbicularis, Boeck. 
“ah oye orbicularis, Boeck, Forh. Vid.-Selsk. Christiania, 1859, p. 2, 
; Hansen, Dijmphna, 1886, p: 78; I. C. Thompson, Trans. Lit. & 
Phil Soe. Liv erpool, vol. vii. p. 37; hon Brady and Robertson, Rep. 
Forty-fifth Meet. Brit. Assoc. 1876, p. 197. 
Body circular. Thoracic segments perhaps with lateral 
processes. Segmentation of abdomen doubtful (Boeck’s 
figure shows three short and one long segment—impossible in 
amature female). Furea broader than long. Anterior an- 
tenn 9-jointed. Posterior antenne 3- (?) jointed. Tube of 
siphon reaches to the middle of the interval between foot-jaws 
and first foot. Inner lobe of maxilla (considered by Boeck as 
mandible-palp) 2-jointed (?), with two sete, outer lobe with one 
seta. Swimming-feet with 3-jointed branches. (Boeck says tive 
pairs of feet, ¢. e. two pairs of foot-jaws, named by him first 
and second pair of feet, and three pairs of swimming-feet ; so 
the figured “‘ pes unus quarti paris”’ is really a foot of the 
second pair. Consequently Boeck has overlooked one pair 
of swimming-feet; and since this pair may be the fourth, 
as well as the third or second, it remains doubtful whether 
the fourth pair has a normal or rudimentary inner branch. 
The structure of the fourth foot remains doubtful, too, if we 
admit * that the specimen described by Boeck was immature, 
and had really only three pairs of feet; this being the case, 
the appendage which Boeck calls the rudimentary foot would 
be the not yet developed fourth pair.) An accurate redescrip- 
tion of thisoldest species of Ascomyzontide is required, perhaps 
not for recognizing the species, but for detérmining the 
systematic position of the genus. If the inner branch of the 
fourth foot is found to be 3-jointed and its sete rudimentary, 
the genus Bradypontius should perhaps be withdrawn. 
Another genus, probably belonging to the subfamily 
Dyspontiine, but quite insufficiently characterized, is 
* This conjecture accords with the above-mentioned segmentation of the 
abdomen ; but the length of body (2 millim.) found by Boeck is greater 
than the length of the ov a-bearing specimen dredged by I. C. Thompson 
(1-65 millim. i). 
