170 CALIFORNIA ACADEMY OF SCIENCES. 



15. PleCOStomUS COrdovse Gunther. 



16. PleCOStomuS lima Reinhardt MS. 



17. Plecostomus macrops sp. nov. 



Type No. 7888. One specimen, .28 m. Rio das Velhas. Allen & 

 St John. 



18. Plecostomus francisci Liitken. 



19. Plecostomus alatUS (Castelnau.) 



ss. Dorsal spotted or uniform dusky. 

 i. Superciliary edge not raised, iuterorbital convex; eye 3^ 

 in snout, 6J in head, 2 in interobital; post-temporal with 

 a long descending process which forms the entire posterior 

 margin of the orbit. lima 16. 



tt. Superciliary edge greatly raised, interobital area con- 

 cave; eye 3 in the snout, 5^ in the head, If in the in- 

 terorbital; post-frontals without a descending process; 

 dorsal uniform dusky. mncrops nov. 17. 



rr. Tip of snout granular; eye 6^ in head. francisci\%. 



qq. Belly partially or wholly naked. 



u. Each of the larger lateral plates with two or three yel- 

 low spots; eye 2 in the interorbital. alaius 19. 

 uu. Sides of the body and the fins with longish yellowish 

 spots; head as wide as long. aurogutattus 20. 

 uuu. Sides of the body usually with round dusky spots; 

 fins similarly spotted or plain. 



V. Occipital bone bordered by two or three nuchal plates. 



w. Caudal plain. iiitkeni 21. 



WW. Caudal with wavy cross bars formed by dusky 



spots. vermicularis nov. 22. 



www. Caudal with two series of spots between each 



two rays. brevicauda 23. 



vv. Occipital bordered by a single nuchal plate. 



X. A single series of large round spots between two 



dorsal rays. robinii 24. 



XX. Two series of spots between two dorsal rays; 



Tipper caudal lobe little shorter than the lower. 



ivuchereri 25. 

 XXX. Spots on the caudal much smaller than those 

 on the dorsal; caudal very obliquely truncate. 



johnii 26. 

 bb. A. 6-8. (Neoplecostomus) 



y. A. 6 microps 27. 



yy. A. 8 granoeus 28. 



