ADDENDA ET COKEIGENDA. 563 



Page 279. Dactyloscopus tridigitatus. 



Mr. Gill has favoured me with a further account of specimens ex- 

 amined by him ; he distinguishes, now, two West Indian and one 

 Californian species. The two former appear to me to be very closely 

 alHed, and identical with the specimens in the British Museum, 

 although they all show slight differences from one another. Mr. 

 Gill distinguishes — 



a. D. tridiriitatiis, from Barbadoes, Cuba, and Key West, with the 



formula: D. 40. A. ;i4. L. lat. 45. 



b. D. poeyi, from Cuba, with the formula : D. 42. A. 34. L. lat. 48. 



The species from California is : — 



2. Dactyloscopus pectoralis. 

 Dactyloscopus poctoralis, (jUI. 



D. 34. A. 28. L. lat. 40. 



Light brownish-yellow, with dark spots arranged in lines, forming 

 the outlines of about six dorsal quadrangular areas, from the angles 

 of which other lines proceed downwards and converge towartls those 

 departing from the angles of the adjoining areas. A transverse blotch 

 posteriorly between the orbits. Four rays diverge in pairs from each 

 orbit ; two dark spots on the crown ; behind and below the orbit is 

 a whitish area, with a dark spot before and behind ; upper angle of 

 the operculum whitish, bordered in front by a dark line or spot. 



Caudal and pectoral tins much longer than in the West Indian 

 species. (Gill.) 



Cape St. Lucas, Lower California. 



Page 279. Add a new genus : — 



Ida. MYXOD AGNUS. 



Myxodagnus, Gill. 



Head rather elongate and acutely conical ; eyes large, elliptical, 

 very closely approximated ; frontal bones extremely narrow. Lower 

 jaw much projecting, with a short compressed flap or barbel in front 

 of the symphysis. Dorsal fin behind the vertical of the anus. In 

 other respects similar to Dacti/loscopus, but with the membranaceous 

 fold between the limbs of the lower jaw much reduced. 



For the knowledge of this genus also I am indebted to the kind- 

 ness of Professor Gill, who has sent me an abstract of the lengthened 

 description which he will shortly publish in the Proceedings of the 

 Academy of Nat. Sc. Phil ad. ; unfortunately it was received when 

 the printing of this volume was nearly completed. 



1. Myxodagnus opercularis. 

 Gill, MS. 



I). 36. A. 38. L. lat. 51. 



The length of the head is one-sixth of the total, or four times tlie 



2 o 2 



