1894.] NATURAL SCIENCES OF PHILADELPHIA. 93 



the body and the limbs behind the carapace are much paler, being 

 usually concealed in the tubular dwelling. 



Nine species of Tauaidoe have been previously recorded from the 

 western shores of the North Atlantic, namely : 



Tanais vittatus Rathke. 



T. hirsKtiis Beddard. 



Leptochelia Snvignyl Kroyer=(L. ah/icohi Harger 9 ). 



L. dt(bia = (L. ahjicola Harger $). 



L. rapax Harger. 



L. (/) filum (Stimpson) Harger. 



Heterotanais limicola (Harger) Sars. 



Leptognathia coeca (Harger) Sars. 



Neotanais americana Beddai'd. 



Tanais vittatus, L. Savignyi {f) and L. (Juhia (J) have been taken 

 at Great Egg Harbor Bay, New Jersey. 



T. /aVs(/^;/s was dredged by the "Challenger" in 50 to 150 

 fathoms off Prince Edward Island. 



Neotanais americana was dredged by the "Challenger" in 1,250 

 fathoms about 200 miles southeast of New York, 



H. limicola, L. coeca and all the species of Leptochelia enumerated 

 have been taken on the New England coast. 



The genus Tanais may be distinguished from all others by the pos- 

 session of one- branched uropods, pleopods on the first three segments 

 only of the pleon and incubatory sacs at bases of the fifth pair of 

 limbs. Sars in his re- definition of the genus says, "uropoda l)revia, 

 simphcia, ramosingulo bi-vel tri-articulato." His figure of T. cavolinii 

 possesses four joints, though Milne Edward's figure has but three. 

 Tanais (Zeuxo) Westtvoodiana has six joints, T. hirsidus has twelve 

 and T. novce zealandae has five, one moi'e than the species just 

 descrilied. 



T. robustus differs from T. vittatus, the only other New Jersey 

 member of the genus, by its greater robustness and tapering body, 

 by the possession of one more joint in the pleon and in the absence 

 of setiferous bands crossing the first two segments of the pleon. 



In the foregoing reference is made to the following papers : 



Beddard, F. E. "Challenger" Reports. Isoj^oda— 1886. 



Harger, O. Report on the ^Marine Isopoda of New England and 

 Adjacent Waters. Report of U. S. Fish Commission, 1878. 



Norman, A. M. and Stebbing, T. R, R. On the Crustacea Iso- 

 poda of the " Lightning," "Porcupine" and "Valorous" Expe- 

 ditions. Transactions Zoological Society of London, 1886. 



