MARINE ISOPODA OF NEW ENGLAND, ETC. 419 



is a row of sette; the dactylus is stroug, with an obtuse tooth on its 

 inner margin. In the second j^air of legs the dactyhis is rather robust 

 and tapers strongly. In tlie sueceediug pairs of legs the dactyli become 

 curved, and, in the posterior pairs, hooked and armed with a comb of 

 slender teeth, while the three i)receding segments are also armed with 

 slender teeth or spines at their distal ends. The constrictions between 

 the thoracic segments are well marked, giving the body a somewhat 

 moniliform appearance. In breeding females, a pair of warts, or sacs 

 of greater or less size are found attached to the under surface of the 

 fifth thoracic segment, and containing eggs or young, according to their 

 stage of development. These sacs often, if not usually, coalesce more 

 or less perfectly before maturity. 



The first three segments of the pleon are not narrower than the last 

 thoracic segment, and are strongly margined, or tufted, at the sides with 

 plumose hairs. These hairs are continued in two transverse rows, one 

 upon the first and another on the second segment near their posterior 

 margins, across the back of the pleon. This character is only im- 

 perfectly shown in the figure, where the transverse rows of hairs should 

 have been more strongly indicated. The last two segments of the pleon 

 are suddenly narrower than the first three. The last is much longer 

 than the fourtb and bears a short tooth at each side near the base. 

 This segment may be composed of two united. The three paii'S of 

 pleopods are nearly alike (pi. XIII, fig. 82), and consist of a basal segment 

 bearing two semi-oval lamellae, which, as well as the basal segment, are 

 strongly ciliated. The uropods are scarcely longer than the last two 

 segments of the pleon, and the basal segment is comparatively small; 

 the second segment is nearly as long as the first, the third about half 

 as long as the second and tipped with setse, with which the first two 

 segments are also provided. 



Length 5.5 """"j breadth 1.1 ™'"; color brown, mottled with lighter 

 above ; beneath, nearly white. 



This species occurred on piles and among algte and eel-grass at 

 IsToank ! , Conn., in the summer of 1871, along with LeptocJicUa aJgieoIa, but 

 in much less abundance. It was described by Eathke from Molde, on 

 the west coast of Norway, and inhabits also the British Isles, and while 

 the present article was going through the press I received, through the 

 kindness of Eev. T. E. E. Stebbing, specimens from Torquay!, England, 

 which confirm my previous determination of our species as identical 

 with the European form. It has been found by J. D. Macdonald "in 

 the excavated wood of piers, in company with Limnoria and CJielura 

 terebrans.'''' It is doubtfully identified by Bate and Westwood with a 

 Mediterranean species, T. CavolinU Edw. On the authority of Lilljeborg 

 I have regarded it as identical with Tanais tomentosus Kioyer, although 

 differing in the number and proportion of the segments of the pleon, as 

 described and figiired by that author. Kroyer's specimens were from 

 ^resund, Denmark. 



