PYCNOGONIDA OF NEW ENGLAND AND ADJACENT WATERS. ,469 



nogonidcD of tkose forms which possess palpi ; aud for this group the 

 name Pasithoidce may be used. The families will then stand as follows : 



A. AnteunsB present and chelate. 



Palpi present Xijm})lw)ilda'. 



Palpi wanting Pallenidoe. 



B. Antenuffi present, siniijle AchcUdce. 



C. Antenna;, wanting. 



Palpi present rasWioidce. 



Palpi wanting Pycnogonidce. 



This arrangement is, it is true, sotaewhat artificial, but it affords a 

 convenient division of the genera, and may, for the present, be retained. 

 Following, is a systematic account of the genera and species. 



Family I, PYCNOGONID.^. 



]!*tcnogonum: Briinnich. 



Body very broad and stout. Antennae and palpi wanting. Acces- 

 sory legs ten-jointed, wanting in the female. Legs stout, dactylus with- 

 out auxiliary claws. 



Pycnogonum littorale (Grom) 0. Fabr. 



Fhalangium littorale Strom, Sondmor, p. 209, PL I, fig. 17, 1762. 



Acarus marimis Pallas, Misc. Zool., p. 188, PI. XIV, figs. 21-23, 176G. 



Pycnogonum halmmrum L., Syst. Nat., ed. XII, I., p. 1028, 1707. — C'lir. Fabr., 

 Ent. Syst., vol. iv, p. 416, 1794.— Latreille, Hist. Nat. des Crust, et dea 

 Insectes, Tom. vii, p. 332, 1804.— Gen. Crust, et Insect., Tom. i, p. 144, 1806. 



Pycnogonum littorale 0. Fabr., Fauna Gronlandica, p. 233, 1780. — Abilgaard 

 in O. F. Miiller, Zool. Dan., Volumen 3, p. 68, PI. CXIX, figs. 10-12, 1789.— 

 Cuvier, E^gne Animal, Aracbnides, PI. 21, figs. 1 to Id. — Milne-Edwards, 

 Hist. Crust., vol. iii, p. 537, PI. 41, fig. 6.— Johnston, Mag. Zool. and Bot., vol. 

 i, p. 376, PI. XIII, figs. 1-3.— Kroyer, Nat. Tidss., Iste Bind, 2det Htcfte, p. 

 126. — Isis, Jahrg. 1846, Heft vi, j). 442. — Voy. en Scand., Laponie, etc.. Crust., 

 PI. 38, figs. 4a-e. — Norman, Kept, of the Brit. Assoc, for the Advancement 

 of Sci. for 1868, p. 301.— Whiteaves, Ann. and Mag. Nat. Hist., Nov., 1872, p. 

 347; Kept, of a second Deep-sea Dredging Exp. to the Gulf of St. Lawrence 

 [in. 1872], p. 15 [Montreal, 1873?]. — Mobius, die wirbellosen Thiere der 

 Ostsee, p. 153, 1873.— Hoek, Niederliindisches Archiv fur Zool., Band iii, 

 3te8 Heft, p. 236, PI. XV, figs. 1-3, 1877.— Verrill, Amer. Journ. Sci., vol. 

 s, p. 38, 1875. — Smith and Harger, Trans. Conn. Acad., vol. iii, p. 10, 1874. — 

 Wilson, Trans. Conn. Acad., vol. v, p. 4, PI. I, tigs, la-h, PI. II, figs. 3a-h, 

 July, 1878. 



Pycnogonum pelagicum Stimpson, Invertebrata of Grand Manan, p. 37, 1853.— 

 Ven-ill, Amer. Joum. Sci., vol. vii, p. 502, 1874. 



f Pychnogonum littorale Nicolet, in Gay, Historia fisica y politica de Chile, 

 Zoologia, p. 308, PI. 4, fig. 8, 1854. 



Plate I, Figures 1 to 3. 



Body very broad aud flat. Lateral processes with scarcely any inter- 

 val between them. Neck somewhat constricted, but broad and stout. 

 Each segment has a prominent conical tubercle in the median line 

 above, and one or two less x>rominent ones on each lateral process. 



