130 Proceedings of the Royal Irish Academy. 



the pectorals, which is not uueomnion iu larval Teleosteans, the present 

 imperfect state of the type of L. pinmitiis makes it ijnpossible for us to make 

 au exact comparison of the two species in -this, respect, though we have no 

 reason to doubt the accuracy of GiJuther's figure. 



The relatively much larger eye of L. piiniatuH may be a youthful character 

 only, and the present state of the type of that species makes any comparison 

 of its scale and fin ray formulae with those of />. hnichi/roJn-s impossible. 



L. piniKitus has only one canine-like tooth on each side of the vomer; this 

 may be a distinction of importance, because, so far as we know, vomerine teeth 

 tend rather to decrease than to increase in number with age. It has 

 certainly some of the anterior dorsal rays considerably prolonged. In 

 L. bracht/coI.KS the first four rays are broken, and, though tlie first ray is 

 slightly stouter than the rest, none of them seem to be stout enough to afford 

 foundation for any considerable prolongation. Moreover, prolongation of the 

 anterior dorsal rays may be a feature of merely sexual importance (cf. Oihih 

 ciiithrhis). 



The following key should suffice to distinguish the two known species of 

 this genus : — 



Li'CONUS, Gtlir. 



1. Head 8, and lenarth to origin of anal fin 



3 times in total length (without caudal); 

 pectoral fins longer than (and probably 

 more than half as long again as) head,^ . L. jnnnatus, Gthr. 



2. Head oi, and length to origin of anal fin 2-^- 



tunes in total length (without caudal) ; 



pectoral fins about f as long as head, . L. hrachycolus, H. & By. 



Lyayivus bracJiycolns is only known from tlie type-specimen which was 

 taken by the Jlclffa on station S. E. 352, 50^ 22' ]S\, 11^ 40' W. 



YIII. — Growth Mai;ks ox Scales. 



An attempt was made to discover whether the scales of the Macrurids 

 showed any markings which would indicate periodic growth. The existence 

 of such markings has been pointed out by Murray and Hjort (1912); but 

 they do not attempt to explain them. 



The form of the Jfacrurid scale is in most cases roughly hexagonal with 

 the posterior and two postero-lateral angles rounded off, the posterior 



' See foot-note on i>. 129. 



