Gobioid Fishes — Gosline 
161 
them (Fig. 3). The anterior of these is made 
up centrally of the symplectic and meta- 
pterygoid and the posterior by the preopercle, 
which has become an integral part of the 
suspensorium rather than a superficial cover- 
ing bone. Both supports run between the 
hyomandibular above and the quadrate below. 
The non-osseus space between the two struts 
is covered externally by heavy jaw musculature 
which so often gives the gobies a fat-cheeked 
appearance. (The necessity for space for this 
musculature may have been the causal agent 
in the development of the peculiar gobioid 
suspensorium.) I am unaware of a similar 
suspensorial structure in any other fishes. The 
closest approach to it may be that of the order 
Gobiesociformes . This structure seems to be 
common to all the gobioids. It is found in 
Kraemeria and Microdesmus , and is figured by 
Smith (1951: 522, fig. 1) for Paragobioides 
copleyi. 
Opercular Series 
The three opercular bones are present in 
all the gobioid fishes examined. I find nothing 
about them noteworthy in reference to the 
present study. 
Gill Openings 
The gill openings of all the species here 
investigated except Kraemeria are broadly at- 
tached to the isthmus. In Microdesmus the gill 
openings are restricted to a subvertical slit 
running partly ahead of and partly below the 
pectoral fins. In Kraemeria the gill openings 
extend far forward, and the gill covers are 
narrowly attached to the isthmus. 
Branchial Arches 
The glossohyal in gobioid fishes has re- 
cently been dealt with by Takagi (1950). He 
believes that the primitive gobioid glossohyal 
is a bar (as it is in most fishes) and that the 
broad fan-shaped and the forked form are 
specializations within the group. 
Fig. 3. Right suspensorium (except palatopterygoid 
strut) and opercular bones, from outside, of: a , Krae- 
meria ', ; b , Microdesmus. fo, non-ossified area; hm, hyo- 
mandibular; IN, interopercle; mt, metapterygoid; op, 
opercle; pg, pterygoid; PO, preopercle; qu, quadrate; 
so, subopercle; SY, symplectic. 
Among the fishes investigated here Pter- 
eleotris has a very long, narrow glossohyal 
(similar to type A of Takagi’s fig. 3), Eleotris 
a subtriangular bar (similar to type B), Micro- 
desmus and Kelloggella a spatulate glossohyal 
(nearest to type C), Gobiodon a triangular 
glossohyal (of type C), Kraemeria a bar with 
a slight fork at the tip (near type F), and 
Awaous a broadly forked bar (of type V). 
Though these glossohyal types agree in gen- 
eral with Takagi’s findings, my inability to 
read more than the summary of his article 
prevents my checking them in detail. 
Another bone that seems to vary greatly 
in both extent and shape is the urohyal. In- 
asmuch as the significance of this variation 
is unknown it will not be described. 
A highly diagnostic character for gobioid 
fishes would seem to be the ceratohyal struc- 
ture and the branchiostegal ray configuration. 
The least specialized representation of these 
features would appear to be that of Eleotris. 
