102 TELEOSTEI : ACANTHOPTERI. — XX. 
DISCOCEPHALI. — Of these various suborders, we notice first 
the DiscocrePHALI, a small group characterized by a singular modi- 
fication of the dorsal fin. 
Famity L. HCHENEIDIDA. (THe Remoras.) 
Body fusiform, elongate, with minute smooth scales; mouth wide, 
with villiform teeth; lower jaw projecting. Spinous dorsal changed 
into a sucking disk placed on top of head and composed of a double 
series of transverse movable cartilaginous plates. Opercles un- 
armed, P. placed high. V. I, 5. D. and A. long, similar; gill- 
rakers short; no pseudobranchie; no air-bladder. Vertebree more 
than 24. Genera 3, species 10. Of the open seas, attaching them- 
selves to sharks, sword-fishes, tunnies, and floating objects, and thus 
carried for great distances in the sea. The relationships of this 
group are still uncertain. Their resemblance to Elacate is such that 
they apparently should not be placed very far away from the next 
family. 
a. Body slender; vertebre 14+ 16= 30; disk of 21 to 25 laminz; not more 
than 4 body. . . . » EcHENEIS, 117. 
aa. Body robust; vertebra: 124+15= = 97; disks more e than % body, of 16 to 18 
Jamine. 
b. Pectoral rays normal, soft. . /.. 4. 2. 3 eos = a) RE 
6b. Pectoral rays stiff, broad, ossified. . . . . RHomBocuirvs, 119. 
117. ECHENEIS (Artedi) Linneus. (éyermis, an ancient name 
meaning one who holds ships back.) 
254. E.naucrates L. SuckinG-FisH. PrGApDOoR. Blackish, 
belly dark; a black lateral stripe; corners of C. pale. Head 54; 
disk 32, shorter than D.; width between P. 73. D.XXI to XXV- 
32 to 41. A. 32 to 38. L. 30. Warm seas. N. to Cape Cod; 
the commonest species, on sharks, etc. (Eu.). (vavxparns, pilot.) 
118. REMORA Gill. (Ancient name, meaning one who holds 
back.) 
a. Dorsal about XVIII-23. (Remora.) 
255. R. remora (L.). Remora. SuckinG-FisH. Uniform 
dusky; head 4; disk 23, longer than D.; width between P.5}. A. 
25. L.12. Warm seas, N. toN. Y. (Eu.) 
aa. Dorsal about XVI-30. (Remoropsis Gill.) 
256. R. brachyptera (Lowe). Sworp-risH Remora. Light 
brown. Head 4; disk shorter than dorsal; width between P. 64. 
A. 26. Warm seas, rarely N.; on sword-fish. (8paxvs, short ; 
arepor, fin.) 
119. RHOMBOCHIRUS Gill. (5du8os, rhomb; yeip, hand.) 
257. R. osteochir (Cuvier). SpEAR-FISH ReEmorRA. Light 
brown; mouth small; disk very large. Head 5; disk 2 21; width 
