THE DISCOBOLI. 17 



the optic lobes are comparatively much smaller. A number of particulars 

 may be mentioned in which Cyclopterus differs from Cottus, as shape, disk, 

 obsolescent pleurapophyses, toothless vomer, cephalic spines, smooth gill 

 rakers, multiplicity of cajca, elongation of intestine, simple bladder, etc., 

 but their character is not such as weighs greatly against those tending 

 toward closer relationship. The branching bladder and the unmodified 

 ventrals of Cottus lose much of their apparent importance as distinguish- 

 ing characters on closer investigation. General form, firmness of skeleton, 

 toothed gill rakers, smaller number of caeca, shorter intestine, well devel- 

 oped pleurapophyses, and other features in which Liparis and Cottus agree 

 better, can hardly be considered of sufficient importance to counterbalance 

 those tending to place Liparis farther away than Cyclopterus. 



The adhesive apparatus on the ventral surface of certain Gobiidte and 

 on the Gobiesocidas formerly caused these forms to be located with the 

 Lumps and their allies. The disk of the Gobies differs greatly from that of 

 the Gobiesoces, and in either case the organ is structurally very different 

 from that of the Discoboles, while there is little in the balance of the 

 anatomy to suggest close affinities with the latter. In fact, modern ich- 

 thyologists, recognizing the lack of anything in skeletal or other features on 

 which to predicate an approach to near relationship, have generally agreed 

 in placing all of the mentioned types at a considerable distance from 

 one another. 



DESCRIPTIONS. 



In the majority of Discoboli the shape resembles that of the larvae of 

 toads and frogs. That portion of the body including the visceral cavity is 

 broad and massive, while that behind the chamber is narrowed and slender, 

 as in tadpoles. In one section of the group, the anterior portion is the 

 longer ; in another, it is the shorter. Though the application of the name 

 was caused by the disk, the latter is not always present ; some species have 

 lost it so completely as to be without evidence of former possession of either 

 disk or ventrals. When present, the adhesive apparatus is formed of the 

 ventral fins, the six rays in each being transformed into ribs for the central 

 portion, which is surrounded by a dermal fold as a margin. The skin varies 

 in the different genera from tough and covered with tubercles to very 

 tender and slim}'. Ordinarily the flesh is described as gelatinous, and the 

 attachments of the skin are not of the most firm, and in some cases are of 



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