Part II - State of New Jersey

180 CRETACEOUS FOSSILSHomolopsis dispar Roberts n. sp.Plate 89, Figure 5Description.-Carapace broadly triangular before the epibranehialangle, quadrate behind it. Rostrum sloped stceply dornn\varrl: lateralprofile straight, dorsal surface hollowed transversely, tip horizontal andbifid. The stout tubular terminal horns of the tip diverge about 65". Theposterior extremity of the cleft between the horns is roundly concaveand as wide as the mesogastric process. Hepatic facet steeply inclined,separated from the epihranchial lobe by a shallom vertieal sulcus. Thelower distal angle of the hepatic facet is armed with a stont tubereleh:~ving a smaller tubercle behind it. Orbits very obli~lne, their superiormargins each armed with a st,rong spine at the inner angle and a smallt,ul)ercle at the onter angle hehinrl the margin. Each protogastric lobebears two large areolar tubercles which point laterally to the epibranchialangle; bctwcen these t,tlbercles there is a shallolv groove !x.ith asmall tubercle at eael~ end. Afesogastric process una1.med ; met,agastricregion snhtriangular, slightly wider than long and armed wit11 a largetubercle at the middle. The groove separating the melagastric from thenrogastric region is bordered by two :mbmedian pairs of short ridges,one along its anterior, the ot,her along its posterior margin. Tl~e innerextremities of each of these fonr ridges terminate on a small tubercle,the fonr tubcreles being arranged in a rectangle that is slightly widerthan long. Cardiac boss lorn, trapeziform, fused laterally at its widestpart with the metabranehial ridges. Anterior to the mesobranchialridge, lying along the outer half of the latter, there is a short transrerseridge which bears a row of fonr granules; these tvo ridges converge laterallyand t,erminate at the inner posterior angle of the epihranehiallobe. Dorsal srlrface of epihranchial lohe drawn npward into a largeconical boss which is directly opposite the mftagastric tubercle; anteriorsurface of the lobe steeply inelinetl ; lateral surface rert,ical. Lateralmargin of branchial region notched by the two branchial grooveswhich continue downwartl and slightly forward on the vertical hranchialwall. Between the notches there is a large marginal tt~herclc anrlbehind the proximal noteh are at least txo tubercles (the posterior estremityof the lateral margin is missing). Ground surface of carapacesmooth; sumlnits of ridges smooth or with an occasional small granule.Measurement of holotype: length of carapace as broken 21 ; width21 mm.Remarks.-I have placed this species in the genus Hon~olopsis eve^^though the rostrnm is hifid. It is distingnishable from the precedingspecies, 11. atlantica Roberts (sapm, p. li!)), of which the rostrnm isunknown, by the triangular shape of the metagastric region and t.hf!smooth, narrow branchial riclgcs. The tip of t,he rostrusu and t,l~e left,rostra1 horn were freed from the matrix aftcr the plate figure had beenprepared.NEW JERSEY GEOLOGICAL SURVEY