Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 213 



hinder lateral margin, which is laminate and cut into three teeth, 

 shaped as in the illustration. The dactyl is very curved, sickle-shaped, 

 acuminate, and closes upon the propodal teeth. The elongate-cylin- 

 drical paired gills arise from the third and fourth thoracic segments. 

 The last three pairs of legs are similar in structure but of slightly 

 decreasing length, prehensile ; the propodus thickened with one ap- 

 proximately median tooth on the anterior lateral margin ; the dactyl 

 about half as long as the propodus, curved, acuminate, its tip closing 

 upon the propodal tooth. 



The females are smaller than the males ; the spiny ornamentation 

 of the body is less pronounced; the second chelipeds are smaller in 

 proportion to the related body. 



Synonymy, — Caprella geometrica Say, Journ. Acad. Nat. Sci. Phila., 

 vol. 1, p. 390, 1818.— DeKay, Zool. of N. Y., Crust., part 6, p. 41, 

 1844 (extra-limital to New York). — "White, List Crust. Brit. 

 Mus., p. 357, pi. 56, fig. 8, 1841 (lists specimens donated B. M. 

 by Say — holds the species distinct from C. acutifrons). — S. I. 

 Smith, in Verrill, Rept. Invert. Vineyard Sound, 1874, pp. 316, 

 382, 40, 567, pi. 5. — Mayer, Paul, Arthostraca, in Zool. Jahrb. fiir 

 1880, pp. 51-63; Mayer says C. geometrica equals C. acutifrons 

 (Leach Mss.). — Latreille, 1816. — Uhler, Chesapeake Zoological 

 Laboratory, p. 26, 1878, reports the species at Fort Wool. — Kings- 

 ley, Standard Nat. Hist., vol. II, Crustacea and Insects, fig. 96, 

 1884.— R. Rathbun, Proc. U. S. Nat. Mus., Ill, p. 1, 1881 ; records 

 the species at Provincetown, Mass. — Stebbing, Rept. Voy. "Chal- 

 lenger," Zool. Amphipoda, vol. 29, pt. I, pt. 2, pp. 104, 207, 224, 

 437, 485, 554, 1636. 



Family: PODOCERIDAE. 



Genus: ERICHTONIUS H. Milne Edwards. 

 EricMonius rubricornis Stimpson. 



Type: Collected in Grand Manaan and believed to be no longer 

 extant. 



Distribution: Abundant in the Bay of Fundy and northward in 

 to the coast of Labrador; less abundant south of Cape Cod, Mass. 

 Littoral to 100 fms., possibly found at greater depths. 



Habits: According to Holmes this amphipod "lives in flexible tubes 

 composed of sand or mud stuck together with a small amount of adhe- 

 sive web-like material." 



