DISCUSSION OF SPECIES AM) THEIR DISTRIBUTION. 53 



Family MICROSTOMID^E. 



ARcroBtomatoida , Gill, Cat. Fish. E. Coast, X. A.. 1861, 51. 

 Microstomida, Gill, Ait. Fain. Fishes, 1872, 16. 



The family Microstomia, although never formally defined by Dr. Gill, is evidently a 

 valid one. separated from Argentinidce by the much smaller number of branchiostegal 

 rays, only three or tour, instead of six to eight, as in Argentinidce. The advanced position 



of the ventrals is a collateral character. 



MICROSTOMA, Cuvier. 



Microstoma, Crviri;. Regne Animal, 1st ed., 1817, n, 184; 1829, n. 285. — GttNTHER, Cat. Fish. ISrit. Mns., 

 vi. 204; Challenger Report, xxn. 218. 



Microstomids, with small mouth, small intermaxillaries, short and broad mamillaries. 

 Small teeth, in narrow series in lower jaw, and on head of vomer. Ventrals in front of dor- 

 sal. Caudal fin furcate, its base squamose. Branchiostegals, 3-4. Pyloric caeca absent. 

 Air bladder large. Scales large, thin, silvery. Adipose tin absent in adults. 



"The evidence as to the bathybial habits of these small fishes," writes Gunther, "is 

 merely circumstantial. They seem to have the same vertical range as Argentina, but are 

 more rarely seen in collections, as the small size of their slender cylindrical body renders 

 their capture very difficult." 



MICROSTOMA ROTUNDATUM, (Risso), Guxther. (Figure 59.) 



Gasteropeleciis microstoma, Risso, I <li t 1l. Nice, 1810, 356. 



Microstoma microstoma, Covier, Regne Animal, ed. 1. 1817, n. 184; ed. 2, 1829, 285. 



Microstoma rotandata, Risso, Eur. Merid., 1827, in, 475, fig. xxxvi. 



Microstoma rotundatum, Gunther, Cat. Fish, Brit. Mns.. vi, 204.— Canesi laxi, op. cit., 130. 



Microstoma argenteum, Covier and Valenciennes, Hist. Nat. Poiss., xvm, 358, pi. 544. 



Body cylindrical, mouth small. Height of body lo to 11 in length. Diameter of eye 2J in 

 length of head, the latter .">.' in total length. Ventrals midway from base of caudal and base 

 of pectoral. Adipose fin usually wanting. Silvery. 



Radial formula: D. 9-11; A. 8; P. 8; V. 10; L. lat.52. 



Known only from Nice and Sicily. It is placed among bathybial forms in deference to 

 the opinion of I>r. Gunther already quoted. The National Museum has a specimen (No. 

 40072) from Messina, sent by the Florence Museum, one of fifteen examples of this very 

 rare form, taken by Giglioli, September 25-28, ls7-">. 



We have had no opportunity of examining another Mediterranean form recently described 

 byFacciohi (Microstoma oblitum, Facciola, Naturalista Siciliana VI, 193.) 



MICROSTOM \ GRCENLANDICUM, Reinhardt. 



Microstomas gramlandicus, Rein'iiakdt, Vhl. Selsk. Naturvid. ng Math. At'lianill.. VIII, 1841, lxxiv. 

 Microstoma grosnlandicum, GOnther, Cat. Fish. Brit. Mns.. \ i, 205.— Gill, Cat. Fish. E. ('. X. Amer. 



"Height of body 10 in Length. Length of head 5 in same. Ventrals under posterior 

 part of ventrals. Adipose fin conspicuous." 



Radial formula: D. 11; A. K»: V. 10. 



This form was found at an early day in the waters of Greenland, but has not since been 

 observed. 



Family BATHYLAGID^. 



Bathylagidce, Gill, Science, in, 620, 1884. (Name only. I 



The family Bathylagidce of Gill was formed for the genus Bathylagus of Gunther. This 

 genus includes live species of small fishes, one of them (/»'. atlanticus) occurring in the 

 Atlantic in depths as great as 2,040 fathoms, another ( /.'. antarcticus) inhabiting the Ant- 

 arctic Ocean at a depth of 1,950 fathoms, and a third (B.pacificus) occurring off the coast. 



