ISOPODS OF NORTH AMERICA. 687 



''Telson: coxio ot),solete; posterior pleopoda (false feet) nearly 

 uncovered; pedunch' (basis) somewhat triangular, broad; accessory 

 lobe badly marked; accessory appendage inserted nearly on same line 

 with ischium, flattened, rounded at the extremit\'; ischium long-, sub- 

 ulate. Species, A. spiniger.'''' — Kinahan." 



ACANTHONISCUS SPINIGER White. 



Acanthoniscus spiniger ^V^ITE, List. Crust. Brit. Museum, 1847, p. 99. — Gosse, A 

 Naturalist's Sojourn in Jamaica, 1851, p. 65. — Kinahan, Proc. Dublin Uni- 

 versity, I, 1859, p. 197, pi. XIX, fig. 4.— BuDDE-LuNi), Crust. Isop. Terrestria, 

 1885, pp. 241-242.— Richardson, Proc. U. S. Nat. Mus., XXIII, 1901, p. 569. 



Locality. — Jamaica. 



" Body covered over with long spines arranged in a double longi- 

 tudinal row, one spine to each ring. In cephalothorax a second row 

 of shorter spines (two to each ring) on each side at junction of cox» 

 and body. 



" Head covered with coarse knobs; two minute spines behind; a 

 raised emarginate ridge marks out front. 



"Coxai of first cephalothoracic somite 

 expanded into a circular lobe; coxaj of sec- 

 ond to sixth somite narrow; seventh some- 

 what quadrilateral. 



"■ Abdominal somites: coxae, first and sec- 

 ond, obsolete; third, fourth, and fifth, nar- 

 row, curved, triangular. 



' ' Telson cordato - pandurif orm : apex fi«- 68i. -acanthoniscus spiniger 



-,. , . . . , (After Kinahan). a, Terminal 



deeply notched, its extrenuties triangular, segment of abdomen. fi,URopoD. 

 produced, acuminate; sides of telson deeply 



incurved at base and then broadly convex. Posterior pleopods: acces- 

 sory filament somewhat flattened; rounded at the extremity, about 

 half length of ischium, and arising from a point distant from apex 

 about a third of total length of peduncle. Ischium long and sul)ulate. 

 Peduncle prolonged as a spine external to origin of ischium. Color: 

 deep chocolate brown black, wnth lighter patches. 



''Locality: Jamaica. 



"The specimen in the British Museum, the only one I have seen, 

 wants the external antenna'; but from the fragments of those that 

 remain, and other characters, an affinity can be traced between this 

 genus and the Porcellionidw. See Remarks on Deto^ infra. 



""The form of the telson is unique; the posterior pleopods show an 

 approximation to Deto; but in the absence of the antenna' it is impos- 

 sible to speak positively." — Kinahan. '^ 



a Proc. Dublin University, I, 1859, p. 197. 



