191 



which now is agreed to have its proper place in Pihwmoplax, and identified it, though with 

 much reserve, with '^ Eucrate' sexdentatus Haswell ^). In reahty the present species has noth'ing 

 to do with that of de Haan, and, as to "Eucrate" sexdetitahts Haswell, it is so insufficiently 

 known as to be better discarded altogether. Miers himself proposed the specific name haswelli 

 for his specimen, for the case the latter would turn out to be distinct. Lately Miss Rathbun, 

 becoming aware of Miers' description of the abdomen, definitely removed the species from the 

 Psetidorhombilinae^ creating a new genus, Hovioioplax^ for it among the present subfamily. 



Carapace and legs are "scantily pubescent", according to Miers ; in my specimen only 

 a few short hairs are observed on the carapace; much more conspicuous, however, is a coarse 

 granulation al over the carapace and over the exposed part of the sternum. The former is 

 moderately vaulted in both main directions, strongly declivous on the lateral branchial regions, 

 the whole surface is sculptured, a cervical groove, though discontinued, is found before the 

 middle of the longitudinal axis of the body, and before this groove a very broad gastric area 

 is found, which is generally not subdivided, but anteriorly two epigastric ridges are seen, separated 

 by a narrow groove, which, immediately behind the ridges, bifurcates and disappears gradually. 

 Between hepatic and branchial regions the carapace is bulging; a cardiac area is separated off 

 from the inner branchial ones, the latter are defined laterally by a conspicuous, broad groove, 

 beyond which the carapace is sloping abruptly downward. 



The front measures, between the bases of the eye-peduncles, nearly exactly one-half of 

 the distance between the outer orbital angles ; it is nearly horizontal, scarcely deflexed, granulate 

 like the rest of the carapace, with an obscure longitudinal groove in the middle ; the anterior 

 margin is perfectly straight, with a very slight notch in the middle, and is distinctly visible in 

 dorsal view ; the lateral margins are divergent backward and thickened and pass insensibly into 

 the concave, almost transverse, superior orbital margins, the external angle of which is acute, 

 somewhat depressed, and not much prominent. The distance between these angles is exactly 

 the same as the length of the carapace. Parting from the external angles the lateral margins 

 of the carapace are divergent in their anterior third portion, finely serrate and armed with 

 two prominent and sharp epibranchial teeth. The anterior of these teeth is placed nearer to 

 the external orbital angle than to the postêrior tooth, it is flattened, and of the same shape as 

 the orbital angle, though conspicuously larger; the postêrior tooth is not flattened, but spiniform, 

 slightly curved, directed obliquely-forward, and between the tips of these teeth the greatest 

 width of the carapace is to be found. Behind the postêrior teeth the lateral margin is not sharply 

 marked off as a prominent ridge, but entirely disappears; in dorsal view of the carapace, 

 however, it describes a sigmoid curve, being first concave and then convex, mainly parallel to 

 that of the other side ; the postêrior margin is slightly concave in the middle. 



The eye-peduncles are very short and thick ; the retina of the eye is of a light horny 

 colour, not black (in spirit preservation) ; the finely-serrate and quite straight inferior orbital 

 margin reaches farther forward at the inner end, where it is cut abruptly, so that a wide space 

 is formed, between this inner orbital angle and the lateral angle of the front, for the reception 



i) Cat. Austral. Crust., 1882, p. 86. 



43 



