222 STALK-EYED CRUSTACEA. 
agrees with the male of P. armiger, barring the usual sexual peculiarities of 
an incubatory pouch and simple caudal limbs. The mandibular palpus and 
carapace have the same form and proportions as in the male. The telson, 
moreover, is truncate and entire, and the maxillipeds and gnathopods are 
devoid of exopods — features that Willemoes-Suhm thought were character- 
istic of the male. The brood-pouch of the “ Blake” specimen consists of 
six pairs of incubatory lamellz and the rudiments of a seventh pair between 
the bases of the first pair of legs or gnathopods. From the posterior side 
of the base of the lamellz of the posterior pair there springs a curled and 
ciliated lobe. This specimen, which is represented on Plate LII., is prob- 
ably the female of Petalophthalmus armiger, or at any rate of a closely related 
species.* The specimen that Suhm took for the female of P. armiger is 
clearly a Boreomysis, probably B. scyphops G. O. Sars, as Hansen + maintains. 
Suhm and Sars both represent the carapace of the male P. armiger with- 
out lateral wings, the postero-lateral angles being obliquely truncated. But 
Sars explains this feature in his text (p. 175) as due to a folding of the cara- 
pace. In the female specimen from the “ Blake” dredgings the carapace is 
produced posteriorly so as to form short, rounded lateral wings, just as in 
P. pacifieus. 
According to Sars, the flagellum of the second antenne is imperfectly 
developed in the type specimen of P. armiger, consisting merely of a biar- 
ticulate peduncle, the terminal portion being absent. This defect is without 
doubt due to mutilation of the type specimen, for in the “ Blake” specimen 
of P. armiger (female), and also in the specimen of P. pacificus (male) secured 
during the cruise of the “ Albatross,” the terminal portion of the flagellum is 
present as a slender lash about equal in length to the terminal segment of 
the peduncle, and composed of about six segments. 
The epipods of the maxillipeds, which Sars did not detect in the type of 
P. arnuger, ave plainly visible in the two specimens of P. armiger and P. pa- 
cificus now before me. ‘They consist of delicate long appendages attached to 
the basal segment of the mavxillipeds, and tucked away under the sides of 
the carapace. 
In the light afforded by the “Blake” specimen of P. armiger, it be- 
* The telson of the “ Blake” female (Plate LIIT. Fig. 2) differs somewhat from the telson of the male 
P. armiger, inasmuch as it narrows posteriorly and is furnished with but seven sete on the posterior margin. 
One of these sete (the shortest) is in the median line, the others form three pairs, the external ones twice the 
length of the next pair inside. 
+ Vidensk. Meddelelser fra den naturhist. Forening i Kjébenhavn for Aaret 1887, p. 212, 1888. 
+ Plate LIII. Fig. 2’, Plate LIV. Fig. 1¢. 
5 
