FISHES OF FAMILY BLENNHDAE 39 



dorsal fork of each posttemporal articulates anteriorly with a process 

 on its respective epiotic. The anterior end of the lower fork attaches 

 by a short ligament to the area of junction of the continuous ridge 

 formed by its respective intercalar and pterotic. The sensory canal 

 passes from each posttemporal into a short tube in its respective 

 supracliethrum at the antero-internal surface of the supracleithrum, 

 where the supercleithrum attaches to its posttemporal. This surface 

 is modified to form a confluent joint with the supracleithrum. For 

 most of its length the internal surface of each supracleithrum is 

 attached to the dorso-external surface of its respective cleithrum. 

 The supracleithral canal is very short and enters the skin of the 

 side where the canal continues as the lateral line canal. The lateral 

 line canal is continuous in its dorsal portion and bears several very 

 short, spaced, ossified tubes (not illustrated). The canal descends to 

 the midside posterior to the level of the appressed pectoral rays and 

 becomes a series of disconnected bony tubes (not illustrated), which 

 terminate below the level of the anterodorsal rays. 



Each cleithrum is a large, roughly cresentic bone with the open end 

 of the arc anterior. The dorsal end of each cleithrum is expanded as 

 an anteriorly extending projection that is attached by ligaments 

 to the rear end of the skull. The ventro-anterior end of each cleithrum 

 is joined to the same portion of the cleithrum of the opposite side, 

 and these together are attached by strands of connective tissue to 

 the median urohyal. 



There are two slender postcleithra on each side. The dorsal end of 

 the upper postcleithrum on each side is flattened, and its external 

 surface is attached loosely to the dorsoposteriormost internal surface 

 of its respective cleithrum, and its internal surface is attached similarly 

 to the external distalmost end of the first epipleural on its respective 

 side. The lower postcleithrum on each side is attached at its dorsal- 

 most end to the anteroventral end of its respective upper postclei- 

 thrum. The two postcleithra on each side are more or less in line with 

 the pleural ribs, and it would seem that they function as a pleural 

 rib protecting the viscera. 



Subdorsally on the external surface of each cleithrum, there are 

 adjacent large and small openings; the large opening exits almost 

 immediately ventral into a large excavation. The small opening leads 

 into a canal that extends through most of the arc of its respective 

 cleithrum and exits just internal to the anterior edge of its respective 

 pelvis. The canal broadens into a large sinus at the level of the 

 coracoid. On the anterior concave surface of each cleithrum at this 

 same level, there are several foramina that enter the sinus. Dorsally 

 just below the large and small openings in each cleithrum, most speci- 



