ACANTHOPTERYGII 697 



Four genera, each with a single species : Anoplopoma (Scom- 

 brocottus), from the North Pacific from Unalaska to California : 

 Triglopsis, from deep water in Lakes Michigan and Ontario ; 

 Cottocomepliorus, from Lake Baikal, and Comephorus from the 

 greatest depths of that lake. As in many bathybial forms, 

 Comephorus is colourless and provided with very large eyes; 

 ventral fins are absent and the skeleton is very thin and papery. 

 As a result of this condition, the second suborbital is not produced 

 over the cheek, a unique exception to the main characteristic of 

 this division ; but no doubt can be entertained as to the propriety 

 of referring it to the neighbourhood of Anoplopoma, since the 

 recently discovered Cottocomephorus may be regarded as a con- 

 necting link between the two genera. Comephorus is viviparous, 

 and dies after parturition. 1 Jordan regards Triglopsis as a relic 

 of a former Arctic marine fauna. 



Fam. 4. Rhamphocottidae. Head incompletely cuirassed, 

 with spines ; basis cranii simple ; two nostrils on each side. 

 Gill-opening narrow, above the base of the pectoral ; gills 3^. 

 Vertebrae 24. Post-temporal short and flat, ankylosed to the 

 skull ; scapula and coracoid well developed, separated by cartilage; 

 pectoral rays inserted on the scapula and on 4 plate-like pterygials, 

 2 of which are in contact with the coracoid. Ventral fins close 

 together, behind the pectorals, with a rudimentary spine and 3 

 soft rays. Spinous dorsal shorter than the soft ; no anal spines. 

 Body densely covered with small prickly scales. 



Ehamphocottus richardsonii, a small fish 3 inches in length, 

 from the north-west coast of North America, is the only repre- 

 sentative of this family. 



Fam. 5. Cottidae. Head not or but incompletely cuirassed, 

 usually with spines ; basis cranii simple ; parietal bones often 

 meeting on the median line ; two nostrils on each side. Gill- 

 membranes free or attached to isthmus; gills 3^ or 4; pseudo- 

 branchiae usually present. Vertebrae 24 to 50, the anterior 

 praecaudals with sessile ribs, the posterior with transverse 

 processes, often directed downwards, or forming haemal arches, 

 bearing ribs and epipleurals. Post-temporal more or less dis- 

 tinctly forked ; scapula and coracoid separated from each other 



1 Cf. Dybowsky, Vcrh. zool.-bot. Ges. Wien, xxiii. 1873, p. 475, and Zool. 

 Centralbl. viii. 1901, p. 475 ; Zograf, Tagebl. zool. Congr. Berlin, No. 8 (1901), 

 p. 9. 



