108 



front is not on a straight line throughout its entire length, in the 

 majority of cases. The crest of the base of the outer antennae is not 

 denticulated. Dana states that the " median region is not crossed by 

 any raised lines ;" while his figure shows them. They were present in 

 all the specimens examined by me, and in this respect the species does 

 not differ from admete. Anterior to the line crossing the middle region, 

 and on either side of the medio.n line of the body are two slight promi- 

 nences; posterior to the median line is another, " which reaches to the 

 posterior tooth on either side." The anterolateral margin is four-toothed 

 as in admete; only occasionally do we find a fifth tooth developed. The 

 carapace is more convex. 



The manner in which the carapace of the admete differs from the 

 above description is briefly, as follows : The lines on the surface of the 

 carapace are more prominent; in place of the two prominences anterior 

 to the line crossing the median region of the body are two short ser- 

 rated lines ; and there are, in addition to these two, others of the same 

 character, anterior to the extremities of the median transverse line. 

 The carapace is more compressed, and " the crest of the base of the 

 outer antennae is evenly and short denticulated." 



THALAMITA PYEMNA, (Herhst) M. Edw. 



Thalamita prymna, M. Edwards, Hist. Nat. des Crust., i, 461. — De Hahn, Faun. Japon. 



Crust., 43, pi. xii, f. 2.— Alps. M Edwards, Arch, du Mus. d'Hist. Nat., 1860, 



X, 360, 

 Thalamita crassimana, Dana, U. S. Espl. Exped. Crust., i, 284, pi. xvii, f. 9. — Stimpson, 



Proc. Acad. Nat. Sci. Phila., 18ri8, 39. 

 Foriunus prymna, Latreille, Nouv. Diet. d'Hist. Nat., xxviii, 44. 

 Cancer ■prymna, Herbst, Krabben. und Krebse, pi. Ivii, f. 2. 



Locality: Palmyra Island, North Pacific. 



The crest of the base of the outer antennae differs somewhat from the 

 description of it given by Dana. This distinguished carcinologist states, 

 that the crest is irregularly divided. On the left side the crest bears 

 three teeth ; two of which are sharp and prominent, and the third is 

 quite small. The latter is situated at the base of the inner prominent 

 tooth. On the right side there have been three prominent teeth, but 

 their apices are broken off, and the crest has the appearance of being 

 <' irregularly divided," as is shown in Dana's figure. The anterior mar- 

 gin of the arm is armed with four spines ; the fourth — counting them in 

 the same precedence as in the two species of the genus discussed above — 



