14 MONOGRAPH OF THE FRESH WATKll HI. 



CHAPTER II. 

 ANATOMICAL OBSERVATIONS. 



1. GENERAL REMARKS. 



IT is not our intention in this place, to present the Anatomy of the Cottoids 

 further than what may be necessary to the complete Zoological discrimination of 

 the genera and species. Nevertheless, if we have given more anatomical detail 

 than may be necessary for the above object, we would have this considered as BO 

 much towards a complete anatomy, which we trust may some day be furnished. 



2. THE BONY FRAME OF COTTUS viscoses. 



PLATE III. Fig. 19. 



The skeleton (Fig. 1), is intended to give a general idea of the internal frame. 

 The first vertebra is concealed by the scapular ; the first and eighth ray of the first 

 dorsal fin are omitted by accident. 



The skull (Fig. 6 9), or that part of the head composed of the occipitals, parie- 

 tals, frontals, mastoids, vomer, nasal, ethmoid, petrosals, and sphenoid, may be sub- 

 divided into two regions. An anterior region composed of the vomer, nasal, eth- 

 moid, prefrontals and part of the sphenoid constituting an arcade over the eyes, on 

 both sides of which are the orbits. The posterior region is more bulky; it is the 

 solid box which contains and protects the brain. 



Seen from above (Fig. 6), and below (Fig. 7), the general form of the cranial 

 box is a little longer than wide, and the width behind, on the occipital region, is 

 considerably greater than in front, near the orbits. The upper surface is smooth, 

 a little depressed in the middle, whilst the occipital region is rather convex. 

 ( Fig. 9.) The profile (Fig. 8) shows more accurately the extent of the two regions ; 

 the orbi to-frontal arcade having exactly the same length as the cranial box ; besides, 

 we observe a character which is peculiar to C. viscoaus, at least amongst the species 

 figured on Plate III. that is the great convexity of that arcade. The same character 

 is very likely to be found in all the species whose external features exhibit a very 

 truncated snout, such as ('. .\ln,f<IH. ('. //// riil'mnnli*. &c. 



The movable Inmes of the left .side ol' the face and head in general are represented 

 isolated in Fi-_ r . ">*. The /</>//(/.////<//// Cl'l] has the form of a right airje; Ixjth of 

 its branches Ix-ing of equal length. The hori/ontal one is a flat ellipsoidal pi ere pro- 



