188G.J PROCEEDINGS OF UNITED STATJ:S NATIONAL MUSEUM. G7 



Xyrichthys by the I'orin of the head, the ])ositioii of the eye.s, &e., was 

 based on ignorance. Tlialassoma is, however, the oldest generic name 

 applied to any members of (he ])resent grouj), and it must be retained. 

 If the group be reunited with Flati/fjlo.ssuH, &c., tlie name Thttln.s.soma 

 should be used for all. 



The generic name Jitlis was first given by Cuvier especially to the 

 Luhrus jidi.s of the Mediterranean, a species referied by Dr. Giinlherto 

 the genus Coris of Lacei)ede. Numerous other species were included in 

 the group by Cuvier, but by Swainson all these others were removed, 

 leaving LabrnsjuUs as the sole species of Julh. Whether Jiilis, as thus 

 restricted, is distinguishable from Coris or not we cannot say, and this 

 question does not concein the American species. All the American 

 Julidincc have large scales, while most of those found in the eastern 

 Atlantic [Julis, Coris) have the scales small. 



Of the American species of Thalasaonia, but one [lucasanum) has 

 been examined by us. The characters given behiW are, therefore, 

 drawn entirely from descriptions. 



ANALYSIS OF AMERICAN SPECIES OF THALASSOMA. 



a. Caudal subtruncate, the outer rays not at all produced; body slender, the depth 

 about 4 in length; ventrals shorter thau pectorals; upper half of body dark 

 purplish, lower half becoming abruptly rosy ; dorsal dark, margined with 

 whitisli ; anal brownish, outer half pale ; caudal yellowish, with two puri)Iish 

 bands ; axil with a purple dot Luc asanum, 12. 



aa. Caudal sublunate, the lobes very slightly produced ; body slender, compressed, 

 the depth about 4 in length; no posterior canine; dorsal spines pungent; 

 Tcntrals much shorter than pectorals; top of head and back brilliant yellow, 

 this color extending on sides of head and to ventrals; a large yellow blotch 

 on caudal fin ; lower parts rosy white ; a maroon baud backward from eye, 

 breaking up on body into a series of six quadrate spots of bottle-green, the 

 last blotch extending on outer rays of caudal; dorsal mostly greenish, with 

 pale margin, a dark blotch between second and fifth spines; pectorals pale; 

 ventrals yellow ( Goode) Nitidu:\i, 13 . 



aaa. Caudal forked, the lobes much produced. 



b. Pectoral without conspicuous dark spot ; anterior half of body deep blue ; head 

 paler; posterior half of body bottle-green; a deep blue baud across body 

 covered by pectoral ; a fainter one behind gill-opening, the two perhaps some- 

 times coalescing; spinous dorsal dark; tip of pectoral dark; caudal pale, its 

 lobes dark blue on the outer part; soft dorsal greenish; anal and ventrals 



bluish Bifasciatum, 14. 



hb. Pectoral tin with a conspicuous spot of iudigo-bluo behind its middle; head and 

 caiulal fin entirely violet-blue ; obscure paler streaks on side of liead ; breast 

 violet, paler thau the head ; bo<ly violaceous, its anterior third paler, the 

 scales posteriorly edged with dull violet {Stelndnchnir) MELAXOCniu, 15. 



Thalassoma lucasanum. 



Julh htcasauns LVM, Proc. Ac. Nat. Sci. Pliil.,142, 1S(J2 (Cape San Lucas); 

 (ilinthor, Cat. Fisli. Brit. Mus., IV, 184, 1802 (Cape San Lucas) ; Jordan &, 

 Gilbert, Proc. U. S. Nat. Mus., 3(37, 1882 (Cape San Lucas) ; Jordan & Gil- 

 bert, Bull. U. S. Fish Comm., 1881. 

 Thalassoma lucasanum J ov6iiu. Cat. Fish. N. Am., 98, 1885 ; Jordan, Proc. U. 

 S. Nat. Mus., 1885, 384 (Mazatlau). 



Habitat. — Gulf of California. 



