10 Prof. P. Martin Duncan — On Galerites alhogalenis, Latnlt. 



3|^ inches. The longest rays of the lower lobe attain a length of 

 21 inches as preserved, but as the point of this part' of the fin is 

 broken off, their original length may be estimated at 2|^ inches. 

 These rays of the lower lobe are more closely articulated than those 

 of the other median fins, yet though the joints become shorter towards 

 the extremities, they never are so short as to be square. The joints 

 also show occasional longitudinal furrows on their ganoid surfaces, 

 and the anterior margin of the fin is bordered by minute and very 

 oblique slender fulcra. The upper lobe possesses a very strong body- 

 prolongation : its fringing rays are fine, and begin to dichotomise 

 about the middle of their length ; the joints are rather longer than 

 broad and apparently smooth externally. 



The peculiar sculpture of the scales, together with the non- 

 denticulated character of their hind margins, separate this species 

 from all others with which I am acquainted. I propose therefore to 

 designate it as Elonicldhys orilioleipis. 



IV. — On Galerites albogalerus, Lamarck, stn. Echinoconus 

 coNicus, Breynius. 



By Prof. P. Martin Duncan, F.E,.S.,etc. 

 "IVTEXT to Ananchytes ovata, there is probabl}'- no fossil Echinoid 

 _Lll which is so well known to geologists and so common in 

 collections as Galerites alhogalerus, Lam. Described by Lamarck, 

 studied by Forbes, and puzzled over by almost every naturalist who 

 has classified the Echinoidea, this common yet most variable form 

 has received a number of synonyms, and has been made to belong to 

 four genera besides that in which it now rests. 



It has been figured over and over again, and its teeth have been 

 illustrated by Stokes and Forbes. It gives the name to the family of 

 the Galeridge of Albin Gray and Desor.^ Eminently Cretaceous in 

 its age, the genus has not yet been found in the Tertiaries ; but in 

 these days of deep-sea exploration and affinity-seeking, the well- 

 known form could hardlj' be without a recent alliance. Thus, in 

 the magnificent Eeport on the " Challenger " Echini, by Alex. Agassiz, 

 Cystechinus, A. Agassiz, a genus the species of which dwell in from 

 1050 to 2225 fathoms, is said to have " the facies of Ananchytes and 

 is closely allied to Galerites" (Eeport, p. 148). 



This statement regarding two very different forms naturally 

 attracted my attention, and from what I believed I knew about 

 Galerites albogalerus, it did not commend itself to my belief. But 

 when I began to study the well-known genus of the Chalk, I found 

 that nearly every palaeontologist who had described the form had not 

 been sufficiently exact, and some had fallen into considerable error. 

 In fact, almost every author fails in the truthful description of the 

 nature of the base of the test of the typical species, of the apical 

 system, of the ambulacra, the position of the periproct (anus), 



1 Character : — Test circular or pentagonal, peristome central decagonular penta- 

 gonal, periproct independent of the genital apparatus either superior or inferior. Pores 

 simple ; divided into 1, Galerites proper with teeth, and 2, Echutonince, without teeth. 



