Bibliographical Notices. 73 



large median element is determined as parasphenoid, on each side of 

 which are bones that appear to be pterygoids. The vomer and 

 palatine are regarded as forming the arrow-head-shaped anterior 

 exposed part of the palate. The mandible is long, straight, and 

 diminishes in depth anteriorly from the condyle. An oval man- 

 dibular foramen is described on the middle of the under surface of 

 the jaw. The teeth are imperfect. One or two palato-vomerine 

 teeth remain, and the maxilla and dentary part of the mandible 

 each carry a row of small, close-set, sharp, subcylindrical teeth, which 

 extend back to the orbits. The dentine is simply plicated. Some 

 larger teeth appear to have been placed behind the palatal teeth. 

 The vertebral column is only known from an imperfect cast. The 

 notochord is represented by a large cylinder, somewhat constricted in 

 the middle of each centrum ; the intervertebral foramina appear from 

 the figure to have been exceptionally long. The author finds that 

 each vertebra consisted of a bony neural arch, from which a bony 

 plate descended on each side and joined the median ventral portion, and 

 he sees in this structure an analogue of the vertebrae of Arcliegosaurus 

 and Eachirosaurus. Each centrum is supposed to support parts of 

 two neural arches. There are impressions of fifteen ribs, which 

 have the usual expanded extremities and double head. The tho- 

 racic shield is well preserved, though the central plate is imperfect 

 posteriorly. It is ornamented with radiating sculpture, most deve- 

 loped in front. It has the usual long rhomboidal form. The lateral 

 plates overlap the anterior part of the median plate and terminate 

 posteriorly in a sharp process, beyond which another small shield is 

 found. The dermal scutes appear to have had the form of oats, and 

 were arranged in oblique rows, forming a chevron pattern, with the 

 angle forward, along the length of the specimen. The notochordal 

 character of the vertebral column, with minor ossifi.cations in the 

 centrum, and the simply plicate dentine distinguish this type from 

 all the large labjrinthodonts except Archegosaurus ; and it differs 

 from that genus in the breadth of the interorbital space, development 

 of the epiotic cornua, in wanting a post-articular process of the 

 mandible, which, on the other hand, has an internal articular 

 buttress ; and it further differs in having the rami of the mandible 

 anchylosed, in having large palato-vomerine teeth, with a few man- 

 dibular tusks forming an inner series near the symphysis, and in 

 having the summits of the neural spines expanded from front to 

 back and transversely. The author is disposed to refer the genus 

 to the Archegosauridae, and it is supposed to be a more specialized 

 type than Archegosaurus, and of aquatic habit ; its geological age 

 is probably Permian. 



The memoir concludes v/ith a list of writings on Labyrinthodonts 

 published since 1874. It is an excellent monograph, elaborated in 

 the author's best manner. 



Ann. & Mag. N. Hist. Ser. 5. Vol. xvi. 



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