374 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Limnoria lignorum — Continued. 



Norman, Rep. Brit. Assoc, 1868, p. 288, 1869. 



Mobius, Wirbellos. Thiere der Ostsee, p. 122, 1873. 



Parfitt, Fauna of Devon, Sess. Crust., p. (19), 1873. 



Verrill, Am. Jour. Sci., Ill, vol. vii, pp. 133, 135, 1874; Proc. Am. Assoc, 



1873, p. 371, 1874 ; This Report, part i, p. 379 (85), 1874. 

 Harger, This Report, part i, p. 571 (277), pi. vi, fig. 25, 1874 ; Proc. U. S. 



Nat. Mus., 1879, vol. ii, p. 161, 1879. 

 M'Intosh, Ann. Mag. Nat. Hist., IV, vol. xiv, p. 273, 1874. 

 Stebbing, Trans. Devon. Assoc, 1874, p. (8), 1874. Ann. Mag. Nat. Hist., 



IV, vol. xvii, p. 79, 1876. 

 Whiteaves, Further Deep-Sea Dredging, GuK St. Lawrence, p. 15, " 1874." 

 Metzger, Nordseefahrt der Pomm.,p. 285, 1875. 

 Meinert, Crust. Isop. Amph. Dec Daniae, p. 77, 1877. 

 Smith, Proc U. S. Nat. Mus., 1879, vol. ii, p. 232, fig. 2, 1880. 

 Limnoria uncinata Heller, Verh. k. k. Zool. bot. Ges. Wien, B. xvi, p. 734, 1866. 

 Stalio, Cat. Croat. Adriatic, p. 211, 1877. 



Plate IX, Figs. 55-.57. 



This species may in general be recognized by its habits, being usually 

 found burrowing in submerged timber, to which, notwithstanding its 

 insignificant appearance, it often proves very destructive. 



The body is subcylindrical, tapering slightly at each end and covered 

 above with short hairs to which more or less dirt usually adheres. The 

 head is narrower than the first thoracic segment. The eyes are lateral and 

 consist of about eight ocelli, one central and the others around it. The 

 antennula3 (pi. IX, fig. 56 a) are short and seem to arise from near the 

 middle of the front of the head. The basal segment is the largest ; the sec- 

 ond and third are of slightly decreasing size; the fourth or flagellar seg- 

 ment is, much the smallest, and tipped with setse. The antennae (pi. IX, 

 fig. 56 h) are more slender than the antennulse, and arise just below their 

 bases and a little farther apart. The first two segments are short; the 

 third slightly longer; the fourth and fifth incrieasing somewhat in length; 

 the flagellum is not longer than the last two peduncular segments, and 

 consists of a tapering segment, followed by a few short terminal seg- 

 ments provided with a terminal brush of setaB. The maxillipeds (pi. IX, 

 fig. 56 c) are slender; the external lamella is semi-ovate, with the inner 

 margin nearly straight, acute, and ciliated -at the tip ; the palpus is 

 five-jointed but short, with the segments flattened, and all but the first 

 ciliated along their inner margins. The outer maxillaj (pi. IX, fig. 56 d) 

 are slender, three-lobed, and ciliated at the tip. The inner maxiUse (pi. 

 IX, fig. 56 e) are also slender, the inner lobe tipped with pectinate bristles, 

 the outer with robust spines. The mandibles (pi. IX, fig. 56/) are some- 

 what elongate, but of a simple form, being curved inward, flattened and 

 chisel-shaped at the tip ; below there is a slight tubercle, apparently the 

 rudiment of the molar process ; externally, above the origin of the palj)us, 

 is a prominent tubercle ; the palpus is short, of three subequal segments, 

 the last furnished with a rather imperfect comb of set*. 



The first thoracic segment is about twice as long as any that follow; 

 it is crossed by a broad, shallow depression, and is rounded at the sides. 



