272 DISCOVERY REPORTS 



remainder. Pelvic 12; origin 2f to 3I times as distant from end of snout as from base 

 of caudal. Pectoral and pelvic fins with a muscular basal lobe. 



In one of the above-mentioned specimens I have been able to see enough of the skull 

 to convince me that Brauer was correct in placing this genus in the family Alepoce- 

 phalidae. The structure of the jaws — the maxillary, two supplemental bones, etc. — 

 appears to be similar to that found in Aulastomatomorpha , Alcock, as described by 

 Henning (1906, Aim. Mag. Not. Hist., (7), xviii, p. 307, fig.). 



Family ARGENTINIDAE 

 Revision of the Genus Bathylagus 



I have been able to dissect a poorly preserved example of this genus, but as it has been 

 in formalin the skeletal characters are difficult to make out. I cannot be certain whether 

 there is a mesocoracoid, but the parapophyses seem to be ventral rather than lateral. 

 Regan (1913, Trans. R. Soc. Edifiburgh, XLix (ii), pp. 231, 289) has placed this genus in 

 the family Argentinidae as defined by him, and I am convinced that it belongs here 

 rather than to the Microstomidae, with which it is generally associated. 



Bathymacrops , Gilchrist, 1922, is 'easily distinguished by the position of the dorsal 

 fin, which is in advance of the pelvics, and by the small anal fin. Microstoma oblitiim, 

 Facciola, 1887, from the Mediterranean, may prove to belong to this family. The anal 

 fin has seven to nine rays, and the origin of the pelvics is immediately behind the dorsal. 

 The body is rather compressed, but in other characters, and especially in the dentition, 

 it bears a close resemblance to Microstoma. 



Synopsis of the Species of Bathylagus 



I. Origin of dorsal nearer to base of caudal than to end of snout. 



A. Dorsal with 12 rays; anal with 13 rays; occipital region normal. i. argyrogaster, n.sp. 



B. Dorsal with 8 rays ; anal with at least 24 rays ; occipital region swollen, with a median keel. 



2. milleri, Jordan and Evermann, 1898 



II. Origin of dorsal nearer to end of snout than to base of caudal. 



A. Anal with 13 rays; depth of body 4J in length. 3. atlanticus, Giinther, 1878 



B. Anal with 16 to 25 rays; depth of body 5 to 7 J in length. 



1. Diameter of eye 2| in head, which is 5j to 55 in length of fish. 4. microcepJiahis, n.sp. 



2. Diameter of eye 2 to 2i (rarely zf) in head, which is 4 to 45 in length of fish. 



a. Origin of anal 25 to 3^ times as distant from end of snout as from base of caudal; 

 base of fin 4I to nearly 6 in length of fish. 

 * Depth of body 6 to ']\ in length; anal with 18 to 21 rays. 



■f Depth of body 6 to 6| in length, length of head 4J to 4J ; interocular width 2% 

 to 3 in head ; origin of dorsal nearer to adipose fin than to end of snout. 



5. glacialis, Regan, 1913 



f f Depth of body 7 to 7I in length, length of head 45 to 4I ; interocular width 4 



or more in head ; origin of dorsal equidistant from end of snout and adipose fin. 



6. gracilis, Lonnberg, 1905 



