76 MONOGKAPH OF THE FRESH WATER HI. 



The numbers 8', 73° and 73'' we have added to the series ; 72 is called supratemporal by Professor 

 Owen. 



n s — neural spines. n' — neuro-caudal plate. 



i n — interneural spines. h' — hsema-oaudal plate. 



(fra— dermo-neural spines. cln' — caudo-dermo-neural spines. 



h s — hjemal spines. pi — ^pleurapophysis. 



■i h — interheemal spines. 



dh — dermo-hsemal spines. 

 a represents the tenth vertebra, with its pleurapophyses and pelvic appendages below. 

 /3 is an anterior thoracic vertebra. 

 6 is a group of five vertebrae, two pelvic and three caudal. 



V belong likewise to the caudal region. 



Fig. 6 — 9. Skull of Cottiis viscosus; Fig. 6 from above; Fig. 7 from below; Fig. 8 in profile; and Pig. 



9 from behind. 

 Fig. 10 — 13. Skull of Cottus FranMinii; Fig. 10 from above; Fig. 11 from below; Fig. 12 in profile; 



and Fig. 18 from behind. 

 Fig. 14 — 17. Skull of Cothts Wihonii; Fig. 14 from above; Fig. 15 from below; Fig. 16 in profile; 



and Fig. 17 from behind. 

 Fig. 18 — 21. Skull of 0. Hichardsonii ; Fig. 18 from above; Fig. 19 from below; Fig. 20 in profile; 



and Fig. 21 from behind. 

 Fig. 22 — 25. Skull of Triglopsis TJiomjysonii ; Fig. 22 from above; Fig. 28 from below; Fig. 24 in 



profile ; and Fig. 25 from behind. 

 Fig. 26 — 29. Skull of Acanthocottns virginianus ; Fig. 26 from above; Fig. 27 from below; Fig. 28 in 



profile ; and Pig. 29 from behind. 

 Fig. 30 — 32. Vertebrae oi Acanthocottus virginianus; Fig. 30, thoracic, with its pair of pleurapophyses or 



ribs ; Pig. 81, pelvic, with its pair of pelvic appendages ; Fig. 32, caudal. 

 Fig. 33 — 35. Encephalon of Acanthocottus virginianus; Fig. 33 from above; Fig. 84 from below; and 



Pig. 35 in profile. 

 Pig. 36 — 38. Encephalon of Triglopsis Thompsonii, twice the natural size; Fig. 36 from above; Fig. 37 



from below ; and Pig. 38 in profile. 

 Pig. 39 — 41. Encephalon of Cottus gracilis, twice the natural size ; Fig. 39 from above ; Fig. 40 from 



below; and Pig. 41 in profile (under the name of C. gohioides on the plate). 

 Pig. 42. An imperfect sketch of the encephalon of C. gohioides, twice the natural size, seen from above 



(under the name of C. gracilis on the plate). 

 Pig. 43 — 45. Encephalon of G. viscosus, twice the natural size; Fig. 43 from above; Fig. 44 from below; 



and Pig. 45 in profile. 

 Pig. 46 — 48. Encephalon of Acanthocottus variabilis; Pig. 46 from above; Fig. 47 from below; and 



Fig. 48 in profile. 



