14 U.S. NATIONAL MUSEUM BULLETIN 2 78 



Aegina longicornis f. spinigera. — Hansen, 1895, p. 130. 



Aeginella longicornis. — Holmes, 1904 (1905), pp. 525-526. — Paulmier, 1905, p. 

 169, fig. 39.— Sumner, Osburn, and Cole, 1911 (1913), pp. 132, 134, 135, 656, 

 chart 102.— Kunkel, 1918, pp. 175-176, fig. 53.— AUee, 1922, pp. 57, 58.— 

 Dexter, 1944, p. 356. — Ferguson and Jones, 1949, p. 442. 



Aegina longicornis nodosa. — M. Rathbun, 1905, pp. 7, 76-77. 



Aegina longicornis spinifera. — M. Rathbun, 1905, pp. 7, 77. 



Aegina longicornis spinosissima. — M. Rathbun, 1905, pp. 7, 77. 



Aegina langicornis. — Briiggen, 1909, pp. 42-43. 



Aeginina longicornis. — Norman, 1905a, p. 46. — Stappers, 1911, pp. 74-76. — 

 Shoemaker, 1930, p. 352 (134).— Procter, 1933, p. 256.— Stephensen, 1933, 

 pp. 59-60, 77; 1940, pp. 69-70; 1942, pp. 430-431, 502, 503; 1944a, p. 49, 

 chart X; 1944b, pp. 135, 148, 159, 162.— Gurjanova, 1936, pp. 568, 580, 588, 

 589; 1964, p. 313.— Elton, 1937, p. 433.— Dunbar, 1954, pp. 784, 788.— 

 Bousfield, 1958, p. 322.— McCain, 1965, pp. 191-192, fig. la; 1966, p. 92.— 

 Cerame Vivas and Gray, 1966, p. 263. 



Diagnosis. — Since this genus is monotypic, the characters of the 

 genus are diagnostic for the species. 



Description. — Body spination variable, smooth to quite spiny; 

 cephalon separated from pereonite 1 by suture. Length of largest 

 male 54 mm, female 34 mm, smallest ovigerous female 9 mm. 



Antenna 1 usually longer than body, flagellum mth up to 26 

 articles. Antenna 2 setose and usually shorter than articles 1 and 2 of 

 antenna 1. 



Mouthparts quite similar to those of typical Caprella (p. IS), 

 lacinia mobiUs of right mandible not distinctly 5-toothed but with 

 several teeth and serrations. 



Propodus of gnathopod 1 with pair of grasping spines, grasping 

 margins of dactylus and propodus only shghtly serrate. Propodus of 

 gnathopod 2 with proximal poison tooth and distal notch, tooth, and 

 rectangular projection, anterodistal margin with triangular projection; 

 basis and ischium with anterodistal projections; carpus mth postero- 

 distal projection. 



Propodus of pereopods 5-7 with pair of proximal grasping spines. 



Abdomen of male and female with 2 pairs of biarticulate append- 

 ages and pair of lobes, medial margin of appendages with numerous 

 minute knobs. 



Variation. — The degree of spination of the body is variable. The 

 most spiny form is illustrated in figure 4j, and there are various 

 degrees of spination; some are almost smooth. Spination seems to 

 vary from spinose in northern waters to smooth in southern; however, 

 spiny forms have been found infrequently in the southern part of 

 the range of this species. 



Figure 6 illustrates the relationship of pereonite length to total 

 body length. The solid black Hues represent individuals, and the 

 dashed lines indicate the linear relationship between pereonite length 



