506 PROCEEDINGS OF THE ACADEMY OF 



fin and the presence of pseudobranchiae, of which no trace is perceptible in 

 Dactyloscopus* 



Dactylagnus mundus Gill. 



The greatest height is rather less than a sixth (-16) of the total length. 

 The head, from the prominent chin to the posterior margin of the subopercu- 

 lum, forms a fifth of the same length, while the caudal forms a tenth. The 

 dorsal fin commences nearly over the second inarticulated ray of the anal fin, 

 and its spines increase in a slightly curved line towards the articulated rays. 

 The oblique levator muscle of each pectoral ray is remarkably developed ex- 

 ternally, and impart to the rays a curve upwards towards the ends. 



The lateral line runs near the back through fourteen scales, is deflected on 

 four, and thence continued along the middle through thirty-six. 



D. X. 31. A. II. 38. C. 11, 1, 4, 4, 1, IV. P. 15. V. I. 3. 

 5 



Scales 14 | 4 J 36 

 5 



Extreme length 5| inches. 



Body Greatest height 16. Least height 16. Least height of tail 4. Great- 

 est width 12. 



Head Greatest length 20. Distance from upper jaw to nape 10. Height 

 at preoperculum 12. Greatest width 12. "Width behind eyes 8J. Height 

 behind eyes 10. Width of interorbital area 2. 



Eye Diameter 3. Distance from snout 3. 



Dorsal (spinous). Distance from snout 23. Height at first spine 3. Height 

 at second spine 4. Height at tenth spine 5^. Height at first ray 5f. 



Anal Distance from snout 27. 



Caudal Length of middle rays 10. 



Pectoral Length IS. 



Ventral Length of inner ray 10. 



A single specimen of this species was obtained at Cape St. Lucas by Mr. 

 Xantus, and is contained in the collection of the Smithsonian Institution. The 

 species is decidedly the giant among the known species of the tridigitate Lep- 

 toscopoids, its length being nearly twice as great as the largest specimen of 

 Dactyloscopus tridigitatus known to me. 



November 4.th. 

 Mr. Lea, President, in the Chair. 



Sixteen members present. 



The following papers were presented for publication : 



"Note on the species of Brachinus inhabiting the United States" 

 and " Synopsis of the species of Colymbetes inhabiting North Ame- 

 rica, etc. By John L. Le Conte, M. D." 



" On the Pedipalpes of North America. By Horatio C. Wood." 



November 11th. 

 Mr. Vatjx, Vice-President, in the Chair. 

 Seventeen members present. 



* Dr. Guiither has kindly informed me that he was unable to find pseudobranchiae in the Dac- 

 tyloscopus tridigitatus, but that there is "a slight swelling at their usual place," which is ascer- 

 tained to be " muscular substance, as seen under the microscope." 



[Nov. 



