58 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



continent, this is the dominant group of fishes. The Notothenioidae 

 also are the only superfamily to contain freshwater members (Cheimar- 

 richthys and Pseudaphritis) . 



Aside from the Gobiesocidae, Draconettidae, and Callionymidae, 

 which herein are removed from the Perciformes entirely, the members 

 of the notothenioid lineage (fig. 12) seem to fall into three or four 

 groups : 



At the base of the whole lineage are the two families Paraper- 

 cidae and Cheimarrichthyidae. These retain predorsal bones and a 

 number of other percoid features that have been lost by the rest of 

 the notothenioids and, for that matter, the other members of the 

 Blennioidei. (Cheimarrichthys does not, however, have an orbito- 

 sphenoid as stated by Lane, 1965). 



A second group is made up of the notothenioids (sensu stricto) , 

 namely the Bovictidae, Nototheniidae, Harpagiferidae, Bathydra- 

 conidae, and Channichthyidae (Norman, 1957). This group is char- 

 acterized by the three pectoral actinosts, by a single nostril on each 

 side of the head, and by its primarily Antarctic distribution; however, 

 the distinction between this and other groups is not as clear-cut as 

 it appears from the literature. The presence of only three actinosts 

 occurs in the notothenioid (sensu lato) derivative Callionymidae and 

 in the "trichonotid" Hemerocoetes, which, with other "trichonotids," 

 has two nostrils on each side of the head, although the first may be 

 very small; but the derivative Callionymidae and also Melanostigma 

 (see under Zoarceoidae) have only one. 



The third group is made up of the Trichonotidae (sensu lato) 

 (Schultz, 1960, pp. 273-277; except Cheimarrichthys, among the genera 

 I have seen). This group contains a wide spectrum of morphological 

 variation; however, the members I have been able to examine have 

 the following features in common : The gill openings extend far forward 

 under the throat, as in the Bovictidae among notothenioid (sensu 

 stricto) families. The branchiostegal rays are seven, except Hemero- 

 coetes, which has six. The ascending process of the premaxillary is 

 attached movably to the toothed portion. At least in Crystallodytes, 

 Bembrops, and Hemerocoetes, the mesopterygoid forms a broad shelf, 

 free posteriorly, but attached to the palatine anteriorly; the palatine, 

 in turn, is attached movably to the pterygoid. Though these characters 

 are quite distinctive, Hemerocoetes with three actinosts may be inter- 

 mediate between the Trichonotidae and the Bovictidae among 

 notothenioid families. 



A possible fourth group is represented by Melanostigma, which 

 (see p. 63) may prove to be merely a pelagic notothenioid (sensu 

 stricto). 



