1894. PROCEEDINGS OF THE NATIONAL MUSEUM. 23 



the inner distal portion of the onter face of the carious. The inner 

 border of tliis area corresponds in position very nearly with the posterior 

 margin of the pterygostoinian cavity; the cavity itself is therefore left 

 uncovered. The only other representative of this genus in the National 

 Museum is a single specimen of H. (liverticulatns, from Mauritius, in 

 which the cavity is longitudinal, its margin formed by two confluent 

 circles. When tlie cheliped is folded against the body, the concave 

 upper margin of the manus and anterior carpus crosses the cavity at 

 its middle, concealing the posterior half, and exposing the anterior 

 half. 



II. abbotti dift'evi^ from other species in the double ridge in the ptery- 

 gostomian cavity, and in tlie carapace marked witli tubercles instead 

 of granulations, rugose lines, or punctfp. 



DECKENIA CRIST ATA, new species. 



Carapace a little more than four-fifths as long as broad, very thick, 

 slightly convex transversely, very convex longitudinally, antero-lateral 

 margins strongly arcuate. There is a prominent tuberculous post- 

 frontal crest, extending across the carapace, sinuous, interrupted at 

 the median line and at the cervical suture, and slightly interrupted 

 behind the base of tlie eye. The median groove extends backward 

 from tlie frontal margin to the postfrontal crest, where it divides into 

 two grooves outlining the narrow anterior portion of the mesogastric 

 region. The cardiacal grooves are shallow; the cervical groove is 

 almost huigitudinal for a portion of its length, then curves outward 

 and ends at the post-frontal crest. The dorsal surface is punctate, the 

 anterior half is covered with S(|uamiforin granules, which, on the ante- 

 rior branchial regions, become tnberculous and tend to form short 

 ridges. The front is about one-third the width of the carapace, detlexed, 

 tuberculous, three-lobed, median lobe more advanced and much nar- 

 rower than the lateral, its margin bent towards the horizontal. The 

 margin of the front and orbit is raised, shining and indistinctly granu- 

 lous. The orbital margin is sinuous, its general direction being outward 

 and forward. Tlie postorbital tooth is acute and more advanced than 

 in D. imitatrix. The epibranchial tooth is smaller and not far behind 

 the postorbital ; it is followed by a row of about twenty small tubercu- 

 lous teeth, forming an antero-lateral marginal line which posteriorly 

 curves upward and inward on the caraiiace. The posterolateral 

 branchial regions are marked by transverse broken raised lines, which 

 are continued on the subbranchial area. The posterior of these lines is 

 the strongest and is continued further inward on the dorsal surface. 

 The suborbital margin is nearly straight, inclined inward and slightly 

 forward, and is finely toothed, its inner angle thickened and adjoining 

 the end of the eflerent branchial channel, which is in advance of the 

 lateral frontal lobe and is visible tVom above. On the subhepatic region 

 are two tnberculous lines concentric to the orbit. The abdomen of the 



