348 



Mr. C. T. Eegan on the Anatomy and 



very large and pharynx very distensible ; upjDer border 

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

 maxillo-maxillaries) meetin'X anteriorly and with their distal 

 extremities attached within the qnadrates, connected by a 

 loose membrane anteriorly with a moval^le ethmoidal ros- 

 trum and for tlie 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 brancliiostegals 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 Iniomi such as the Synodontidce, which approach them 

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

 (c/. Ann. & Mag. Nat. Hist. (8) vii. 1911, p. 121). 



SOC 



A. 



Diagrams of upper surface of skull in A. Qastrostomus bairdii, B. Sacco- 

 pJtnry7i.v a?nptiUaceus, and C. Saui'ida nebiilosa. (A after Ziig-mayer's 

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

 froutals.) 



eth, mesethmoid ; leth, lateral ethmoid ; /, frontal ; p, parietal ; spo, 

 sphenotic ; ptu, pterotic ; ejio, epiotic ; soc, supraoccipital ; eoc, 

 exoccipital. 



The skull of the Synodontidse has much in common with 

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

 and greater size of the whole poatorbital portion of the 



