158 BULLETIN 201, UNITED STATES NATIONAL MUSEUM 



apex terminates in a single stout spine and each lateral margin has 

 from 10 to 12 small regularly arranged spines along the distal half 

 of the margin, the proximal part of the margin being smooth. There 

 is a pair of plumose setae at the base of the cleft. In P. abyssi the 

 telson is much shorter, only about one-third longer than broad at the 

 base, and there are no plumose setae at the base of the cleft. Otherwise 

 it has the same general structure as in P. dactylops. 



Figure 59. — Pseudomysis dactylops, new species: a, Anterior end to show rostral plate and 



eyes, X 20; b, telson. 



(4) It appears to be a smaller species than P. abyssi. Both the 

 type specimens measure about 30 mm. but have the incubatory lamellae 

 fully developed and are thus adult. Sars' types of P. abyssi measured 

 35 mm., but the incubatory lamellae were still very small and unde- 

 veloped. Hansen gives 45 mm. as the length of an adult female with 

 fully developed marsupial plates and 42 mm. for an adult male. 



It is unfortunate that the antennal scale and uropods in both speci- 

 mens are so broken that I am unable to give comparative measure- 

 ments. What remains of them is, however, sufficient to show that 

 they are essentially of the same form as in P. abyssi. The inner 

 uropod has a row of spines extending along the inner margin from 

 the statocyst almost to the apex. 



