MARINE ISOPODA OF NEW ENGLAND, ETC. 



371 



Specimens examined. 



1224 

 2053 



2052 

 2049 

 2050 

 2051 



Locality. 



Florida 



Great Egg Harlwr, N.J. 



New Haven, Conn 



.Savin Rock, New Haveu . 



Stony Creek, Conn 



Vineyard Sound, Mass . . . 



....do : 



..:.do 



Provincetown, Mass 



....do 



Bottom. 



L. w. 

 L. w. 



L. w. 

 L. w. 



Kocky , 

 Rocky . 



Eel -grass - 



"WTien col- 

 lected. 



Received from - 



April, 1871 



, 1871 



, 1871 



, 1875 



Aug.—, 1879 

 Aug.—, 1879 



Smithsonian 



Inat 



Smith &VerrUl 

 S. I. Smith.... 



U. S. Fish Com, 



....do 



....do 



....do 



....do 



Dry. 

 Ale. 



Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 

 Ale. 



VIII.— LIMi^OEIID^. 



Body compressed ; antennulne and antennse short, subequal; mandi- 

 bles palpigerons, formed for gnawing ; feet not prehensile, all similar, 

 with short, robust dactyli ; epimera united with the thoracic segments ; 

 pleon of six distinct segments ; pleopods similar in form throughout ; 

 uropods lateral, biramous. 



This family as constituted above contains the single genus Limnoria 

 Leach, which appears also to contain but few, or perhaps a single, species* 

 of wide distribution. This genus was placed in the tribe Asellotes 

 liomopodes with the Asellidw by Edwards, without, however, having 

 examined the animals himself. He has been generally followed in this 

 arrangement by later authors. Previous authors had associated the 

 genus, as it appears to me more justly, with SplKBroma and the Cymo- 

 thoidce in the wide signification of the latter term. White, in his List 

 of British Crustacea, used the name Limnoriadm to include this genus 

 with the AselUdfc. I have j)refeiTed to constitute a new family for the 

 genus, which has, however, evident relations with the Sphwrotnidcc, and 

 perhaps should yet be united with that family. 



Under the circumstances family characters can scarcely be se])arated 

 with certainty from those of generic or even of specific value only, but 

 for the puri^ose of comi)arison with other families certain important char- 

 acters may be here stated. The body is somewhat depressed dorsally, 

 but is also compressed at the sides, and when extended is sub vermiform. 

 It is nearly capable of being rolled into a ball, as in the genus Sphceroma. 

 The head is of moderate size and strongly rounded above, as in Sphce- 

 roma, and the eyes are widely separated and on the sides of the head, a 

 condition not usual in the AseUidce. The antennulce are short and stout 

 and the basal segment is but little larger than the second ; the flagellum 



*It i.s perhaps hardly necessary to remark that L. xylophaga Hesse, Ann. Sci. nat., 

 tome X, p. 101, pi. ix, 1868, is not an Isopod. According to Prof. Smith it is Chelura 

 terebrans Philhpi, a boring amphipod often found associated with Limnoria. See an 

 article by that author in the Proceedings of the U. S. National Museum, 1879, vol. ii, 

 pp. 23-2-235. 



