348 



Mr. C. T. Regan on the Anatomy and 



very large and pharynx very distensible ; upper bordor 

 o£' mouth formed by a single pair of slender bones (prjB- 

 raaxillo-maxillarles) meeting anteriorly and with their distal 

 extremities attached within the quadrates, connected by a 

 loose membrane anteriorly with a movable ethmoidal ros- 

 trum and for the greater part of their length with the 

 suspensorium ; lower jaw of dentary, articulare, and angulare ; 

 mandibular rami slender, loosely united at the symphysis and 

 connected by a broad distensible membrane; suspensorium long 

 and directed obliquely backwards, of two bones, iiyomandibular 

 and quadrate, which are movably articulated ; opercular bones 

 absent and branchiostegals vestigial ; branchial arches and 

 pectoral arch far behind the head, with skeleton reduced and 

 little ossified. Skull with much cartilage, the membrane 

 bones very thin ; parietals meeting in front of the small 

 supraoccipital ; no exoccipital condyles. Vertebral centra 

 co-ossified with arches, which are reduced, the neural arches 

 appearing as paired, erect, spine-like processes ; no ribs. No 

 air-bladder. Gonoducts normally developed [fide Zug- 

 mayer). 



The whole structure of the Lyomeri is quite unlike that of 

 the Apodes ; in my opinion they may well have been derived 

 from luiomi such as the Synodontidje, which approach them 

 in the short snout, wide mouth, oblique suspensorium, &c. 

 [cf. Ann. & Mag. Nat. Hist. (8) vii. 1911, p. 121). 



Diagrams of upper surface of skull in A, Gastrostomus bairdii, B. Sncco- 

 jiJiarpi.v nniptiUaceus, and C. Saurida 7iebulosa. (A after Zugraayer's 

 figure, modified by omission of sutures that appear to subdivide the 

 froutals.) 



eth, mesetlimoid ; leth, lateral ethmoid ; /, frontal ; /), parietal ; spo, 

 spheuotic ; pto, pterotic ; epo, epiotic ; soc, supraoccipital ; eoc, 

 exoccipital. 



The skull of the Synodontidpe has much in common with 

 that of the Lyomeri, and the greater width of the pterotics 

 and greater size of the whole po-;torbital portion of the 



