518 



BULLETIN OF THE BUREAU OF FISHERIES. 



Ericthonius rubricornis (Stimpson). 



Ceraptu rubricornis Stimpson, Marine Invert. Grand Mann, p. 47, fig. 33, 1853. Bate, Cat. Amphip. Brit. Mus., p. 265, 



pi. xi.v, fig. 4, 1862. Smith, Kept. U. S. Fish Com., 1871-2, p. 565, pi. iv, fig. is. 

 EHchthonius difformis Smith (not Milne-Edwards), Trans. Conn. Acad. Sci., Vol. IV, 1880, p. 278. 



Eyes nearly round; the lateral lobes of head projecting strongly forward; first antenna- but little 

 longer than second, first joint shorter than head, a little over half the length of second which is subequal 

 tn third; fiagelluin short; second antenna with last basal joint a little lunger than preceding one; fla- 

 gellant short, and furnished like peduncle with long seta 1 on lower margin; first gnathopods with 

 merits produced below into a triangular process; carpus large, widening distaUy; hand smaller than 

 carpus, narrowed at base, about two-thirds as broad as long, palm a little convex and cut into minute, 

 narrow, acute teeth; finger armed within with a few short spines with a few smaller spines or acute 

 denticulations between them; second gnathopods in male very large; carpus produced below propodus 

 into a large acute process; propodus oblong, with a prominence near the distal end of lower margin; 

 in the female the carpus produced into a lobe which extends below propodus about as far as tip of 

 closed dactyl; hand ovate, palm very oblique, convex, armed above with a few pairs of spines between 

 which the dactyl closes; first and second peraeopods short, basal joints large subovate, though more 



Ericthonius rubricornis. Newport, R. I. 



convex in front; merus expanded ami produced downward in front; dactyl long and slender; last pair 

 of perseopods considerably longer than preceding; second and third uropods with margins acute and 

 cut into minute narrow, acute serrations; third uropods with ramus subcorneal, curved, shorter than 

 peduncle and having two or three short spines at the tip: telson emarginate, lobes armed with nume- 

 rous, very short, hook-like spines. 



"Color on the back dark, mottled gray; epimera blackish; terminal articles of the four antenna' 

 bright red; hands yellowish." (Stimpson.) 



Length, 9 mm. 



Labrador; Grand Manan; Bay of Fundv; whole coast of New England; common near Woods 

 Hole. 



This species lives in flexible tubes composed of sand or mud stuck together with a small amount 

 of adhesive, web-like material. According to Stimpson the tubes occur attached to rocks or other 

 objects, generally in large groups. This species is found in shallow water, but Professor Smith states 

 that it may extend to a depth of 100 fathoms or more. It is more common north than south of (.'ape 

 Cod. South of Cape Cod it has been reported from Vineyard Sound by Smith. I have taken it at 



