20 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



from wliicb it is distiuguisbed generically by tbe obsolete eyes, and spe- 

 cifically by the characters given in tbe following description: 



Body elongate, posteriorly mncb compressed, not mucb depressed 

 anteriorly. Head depressed, witb tbe cleft of tbe montb nearly hori- 

 zontal and one-half tbe length of the bead, the maxillary reaching a 

 vertical line drown across tbe i^robable position of tbe eye. Eyes invis- 

 ible, covered by tbe skin; snout rounded; the jaws equal, or very 

 nearly so, tbe lower jaw in a r^reserved specimen seeming to be very 

 slightly produced. Both nostrils are provided with a flap. 



A narrow band of villiform teeth in each jaw. Tbe gill-membrane is 

 united to the isthmus, and tbe branchial cleft is equal in length to tbe 

 distance between the first and second dorsal fins, or one -tenth of tbe 

 length (from snout to base of caudal). 



A groove has its origin immediately in advance of first dorsal and 

 extends medially nearly to tip of snout. 



The fii-st dorsal fin is composed of two flexible sjiines, and is equidis- 

 tant between the snout and the base of the caudal fin ; the insertion of 

 tbe second dorsal is not much in advance of vent, while the insertion of 

 tbe anal is opposite tbe fifth ray of tbe soft dorsal ; tbe last rays of tbe 

 posterior dorsal are slightly longer than its anterior one, and the fin 

 terminates opposite tbe anal, which is similar to tbe soft dorsal. A 

 very small anal j^apilla may be seen. 



Vertical fins low; caudal small, pointed; ventrals forming a disk, 

 which is not adherent to the belly ; pectorals like the caudal in form, 

 their free tips extending beyond the ventrals, though not approximating 

 the first dorsal, and very remote from tbe vent. 



Body entirely smooth, wholly free from scales, tubercles, or asperities 

 of any kind. 



Tbe type specimen has been presented to tbe Kational Museum, where 

 it is numbered 27466. 



This species is doubtless tbe type of a distinct genus, which may be 

 called Othonops {ch'}t'r>rj, veil; w^'-, eye). This genus is distinguished from 

 GrystalJofjohhis by the concealed eyes, these organs being large and 

 conspicuous in C. nilssoni^ and possibly also by the absence of tbe sexual 

 differences in dentition, so marked in Crystallofiohius, the male of C. 

 nilssoni being provided with strong canines. Tbe remaining genera of 

 Gohiinw have five or more dorsal spines, except Benthophilus, which, witb 

 three dorsal spines, has the skin verrucose. 



Since the above was in type three more specimens have been obtained 

 at the same locality, the measurements of the largest of which are 

 included in tbe table below. 



On examination of this specimen, 2f inches in length, I find further 

 characteristics. 



In this examjile, tbe fins are better preserved and show their normal 

 form, tbe caudal and pectoral being rounded tbe pointed appearance 

 of those fins on the type sx^ecimen probably having been caused by 



