A NEW SUBSPECIES OF MARINE ISOPOD FROM TEXAS — MENZIES 579 



and in having a greatly elevated mediodorsal cephalic lobe, which is 

 bi- or tri-tuberciilate at its apex. In specimens of E. attenuata the 

 frontal lamina is narrow and pointed and the cephalon, though slightly 

 swollen dorsally, lacks any elevated apically tuberculate lobe. 



Concerning E. f. filiformis, Harger and Richardson state: "The 

 angulated epimera are evident from above in front of these [posterior 

 external angles of first two thoracic segments] projections" (Harger 

 1880, p. 355), and "In the first two segments the lateral parts are 

 produced in very acute processes, one process on either side of each 

 segment. Just anterior to this process is the epimeron, which is also 

 acutely produced, but lies underneath the lateral portion of the seg- 

 ment in a lower plane. The epimeron of the second segment is 

 bilobate, the upper division, in a dorsal view, concealing the lower 

 lobe, which is also very acute" (Richardson 1905, p. 402). These 

 statements are subject to criticism in that they present an erroneous 

 picture of the species. As was said before, the first peraeona somitel 

 lacks any clearly separated epimeral plate, that which Richardson 

 and Harger considered an epimeron being merely an anterolateral 

 expansion of the first somite. The epimeral plate of the second 

 somite consists only of what Richardson considered the "lower lobe." 

 It is almost completely concealed from view dorsally, not by a dorsal 

 epimeral lobe, but by an anterolateral expansion of the second somite. 

 Both Richardson and Harger failed to mention the conspicuous raised 

 posterior cephalon area, which is separated from the anterior and 

 larger part of the cephalon by a deep transverse groove. This area 

 is present in both subspecies. 



Female specimens of both subspecies appear to have the angulate 

 lateral and supralateral processes more developed than do male spec- 

 imens. The one male specimen of E.f. fdiformis that I have examined 

 has the posterolateral expansion of the second somite reduced to a 

 very small lobe, whereas in two ovigerous females this expansion is 

 nearly as large as the anterolateral expansion of that somite. No 

 nonovigerous specimens were examined. 



LITERATURE CITED 



Harger, Oscar. 



1880. Report on the marine Isopoda of New England and adjacent waters. 

 Report of the U. S. Commissioner of Fish and Fisheries, pt. 6, 

 pp. 297-462, pis. 1-13. 

 Richardson, Harriet (Mrs. Harriet Richardson Searle). 



1905. A monograph on the isopods of North America. U. S. Nat. Mus. 

 Bull. 54, 727 pp., 740 figs. 

 Say, Thomas. 



1818. An account of the Crustacea of the United States. Jouru. Acad. 

 Nat. Sci. Philadelphia, vol. 1, pp. 423-458. 



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