Structure and Classification of the Asterolepidio. 43 



lepis by Lahusen (11), whose opinion I can amply corrobo- 

 rate. Its remains, as they occur at Scat Craig, near Elgin, 

 are very fragmentary ; but I think they are identifiable with 

 those which occur at Heads of Ayr in a more perfect state. 

 Tubercles of the surface confluent, sometimes into tortuous 

 ridges, more generally forming a reticulation, the stellation of 

 their bases often observable ; limbs with the proximal joint 

 proportionally long and slender. 



B. macrocephalus, Egert., sp. {^=iPtericlithys macrocephalus, 

 Egert.). — The long arms and the shape of the anterior parts 

 of the ventro-lateral plates clearly show that this minute 

 species is a Bothriolepis, and very closely allied to B. hydro- 

 philus, Ag., sp. This is quite evident from a glance at Sir 

 Philip Egerton's figures (9) ; but I have also carefully 

 examined the type specimens in the British Museum. The 

 body-plates are sculptured with a delicate reticulate pitting 

 also resembling that of B. liydrophilus. 



In the Geological Magazine for this month I have 

 named and briefly defined two additional species, viz., 

 B. giganteus, Traq., from the Upper Old Eed of Alves, near 

 Elgin, and B. obesus, Traq., from a similar horizon, near 

 Jedburgh. 



Microbe ACHius, Traquair, 1888. 



{ = Pterichthys, pars, C. W. Peach ; Microbrachius, Traq., Geol. Mag., 



Nov. 1888.) 



The small species discovered by the late Mr C. W. Peach 

 in the Lower Old Eed of John o' Groat's, and named by 

 him Pterichthys Dickii} shows some peculiarities which seem 

 to me to be decidedly of generic value. 



It is small in size, head and carapace together measuring 

 only about 1 J inches in length. In shape it resembles Bothrio- 

 lepis, having the carapace generally depressed and broader on 

 the upper than on the under surface. On the upper surface 

 the anterior margin of the carapace forms a deep re-entering 

 angle (see PI. II., Eig. 8) or emargination, so that the antero- 

 external angles of the anterior dorso-lateral plates project 

 considerably in front. 



^ British Assoc. Rep., 1867. 



