Notes on the Suckei' Fishes, Liparis and Lepadogaster. 149 



Now, seeing C. lumjms grows to the length of 24 inches, and 

 3 inches may be considered the full development of L. 

 Decandolii, we should have had the latter furnished with a 

 developed sucker at about 3 mm., or say one-half the size at 

 which it arrives without a show of disc. I have not had an 

 opportunity of watching the development of the disc of 

 Liparis Montagui ; but from its formation I should predicate 

 an early development, as in the case of C. lumpus, to which 

 its disc is allied. 



It would appear as if a slender body and weak vertebrate 

 system had developed, in the case of Gobius and Lepadogaster, 

 a habit of clinging to the seaware and sea bottom that 

 stimulated the pectoral region to meet the necessities of the 

 situation, and, in the case of Lepadogaster, to cushion itself, 

 the pectoral fins curving around the swelling bosom of the 

 fish. Between these cushions depressions were left, and 

 these proving very advantageous to the fish by their sucker 

 action, the advantage was pursued by nature, and trans- 

 mitted. In the case of Gobius (Fig. 9), the cupping action 

 was wholly performed by the fins, the rays of the pectorals 

 strencrtheninoj and stiffenino;, the better to meet the difficultv. 

 This is much inferior to the true suckers in effect, the Gobius 

 being upon the whole an active race, and frequenting less 

 exposed situations. They have, indeed, become partly 

 fresh and brackish water fish, and their suckers are so far 

 makeshifts. 



Although the small cushion-like discs of Cyclopterus and 

 Liparis are the truest suckers, yet the species of Lepadogaster 

 are perhaps the most truly sucker fish. This especially 

 applies to L. Decandolii (Day), which is really a sucker fish 

 all the way forward from the sucker proper itself. Two- 

 thirds of its length, and practically three-fourths of its weight 

 and horizontal surface, is a sucker. By sucking up its lower 

 jaw, and allowing its cartilaginous framework to rest on any 

 object, the front jaw adds its sucking action to the sucker 

 proper. This is aided by the plentiful discharge of mucus, 

 in which this species emulates the Unctuous Sucker, L. 

 linearis. 



The sac of Lepadogaster Decandolii was quite absorbed 



