420 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Hemus analogus Rathbun 

 Plate Y, Fig. 6 ; Plate 47, Fig. 1 



Hemus analogus Rathbun, 1898, p. 573 ; 1925, p. 347, pi. 124, figs. 2, 3. 

 Not Finnegan, 1931, p. 623. 



Type: Female holotype, U.S.N.M. No. 21573, length 8.2 mm, 

 width 6.5 mm. 



Type locality: Southern part of Gulf of California, Mexico, 10 

 fathoms, Albatross station 2828. 



Localities subsequently reported, with collectors: Known only from 

 the southern part of the Gulf of California, in the vicinity of Latitude 

 24° N. Specimens from Taboga Island, Bay of Panama, reported by 

 Finnegan, are believed to belong to the following new species. 



Atlantic analogue: Not the Pacific analogue of Hemus cristulipes 

 A. Milne Edwards, as stated by Rathbun (1925, p. 345), but a Gulf 

 of California endemic species. 



Diagnosis: Front narrow, sides arched, tips approximated. Orbits 

 raised, not deeply indented, no preorbital granule. Cardiac region high, 

 encroaching on branchial and intestinal areas; two indistinct lateral 

 teeth. Meral shields narrow, convex, margins weakly denticulate. Sec- 

 ond movable antennal segment small, oblique. Male first pleopod with- 

 out lateral flange. 



Description: Carapace widest at branchial level, hepatic margins 

 parallel, gastrocardiac ridge irregularly sculptured, cardiac region grossly 

 protuberant, encroaching upon adjacent branchial and intestinal regions, 

 carapace otherwise smooth and microscopically punctate. Front small, 

 triangular, deflexed, edges slightly convex, a median granulate ridge, the 

 terminal granule forming, with two closely approximated outer gran- 

 ules, a minute tridentate tip. Orbits swollen, considerably elevated above 

 front, margins not deeply indented, anterior angles rectangular, a closed 

 superior fissure. First movable antennal segment longer than broad, outer 

 margin arching parallel to margin of front, finely crenulate, and hairy; 

 second movable article small and obliquely directed ; of the flagellar arti- 

 cles only the first cylindrical and swollen. Hepatic regions smooth, con- 

 cave, not prominent, anterior portion of carapace, as outlined by the 

 orbits and the anterolateral margins, rectangular. Gastric region elevated, 

 roughly triangular with backward-pointing apex, contour broken by a 

 complex series of sculptured ridges extending onto the high and domi- 

 nant cardiac region. On either side of the narrowest point of the gastro- 

 cardiac ridge a slight depression, laterally a branchial ridge leading to 

 the larger of two marginal prominences. A similar but smaller ridge 



