244 E. Ray Lankester — On a new Heterostracous Fish-shield. 



orbital notch they are also disposed, in correspondence with the in- 

 dented contour-line. Other irregularities in the surface-striations 

 are best appreciated by an examination of the figure, which is a 

 faithful representation of the specimen, restored only in so far as 

 one side is conclusive as to the other. 



On this shield are a very large series of those minute indentations 

 arranged in linear series — looking like short scratches made with a 

 pin on the surface of a soft substance — the existence of which I 

 have pointed out and figured in ScapJiaspis Lloydii, and in Pteraspis 

 rostratus and Crouchii. They are well seen in the restorations, figs. 

 8 and 9 of pi. vii. and in figs. 1 and 4 of pi. i. of the Monograph. 

 There is little doubt that they are the sites of soft tegumentary struc- 

 tures, in all probability of those characteristic sensory-follicles of 

 fishes, with which they agree in disposition. The occurrence of 

 these " pits " in Scaphaspis and Pteraspis is an additional piece of 

 evidence, confirmatory of the fish-origin of the shields of Heterostraci, 

 which Kunth has ignored. The disposition of the pits in Jlolaspis 

 will be best understood by an examination of the figure. (Plate X.) 



The detection of this new form of Heterostracous fish is satisfactory 

 on other grounds besides the demonstration it afibrds of a transition 

 from the simpler form of Scaphaspis to the more elaborate Pteraspis. 

 It justifies the expectation that the Cornstone fisheries have not yet 

 been exhausted by the geologists of the Welsh border, and we may 

 with hopefulness urge them to continue their labours. Well-preserved 

 bodies with fins and scales of Pteraspis and Scaphaspis, additional 

 evidence of the post-cephalic scutes of Zenaspis Salweyi, and alto- 

 gether new forms of allied genera, are waiting for their hammers. 



In addition to Kunth's and Magister Schmidt's expressions of 

 dissent, there is yet a third attack upon some of the views put 

 forward in my Monograph which has to be met, and is in fact 

 answered by what has been said above. Von Eichwald, in a paper 

 presented to the Society of Naturalists of Moscow, 3rd October, 

 1871, has some observations on Palceoteuthis. I am acquainted with 

 his paper through a translation contained in M. de Lacaze Duthiers' 

 admirable Archives de Zoologie, Jan., 1873. With all due regard to 

 Eichwald's opinion, I must point out that it is lamentably devoid of 

 basis. If he had only seen a few or even one specimen of each 

 genus from our English localities, he could not possibly have main- 

 tained it. Eichwald admits that Pteraspis (as limited by me) is a 

 fish, but he maintains that Scaphaspis is a cuttle-bone, and particu- 

 larizes Scaphaspis (Palceoteuthis) Dunensis, and Sc. Kneri. The 

 fact is — which Eichwald has never had an opportunity of observing — 

 that the minute markings and structure of Pteraspis and Scaphaspis 

 (Sc. Lloydii, rectus, and Sc. Kneri especially), ai'e so exactly like 

 those of Pteraspis that their agreement is appealed to as support for 

 the view that they are as Dr. Kunth maintained — parts of one 

 animal. That whatever may be the nature of Pteraspis, the same 

 nature belongs also to Scaphaspis, is beyond all possibility of doubt 

 established. 



I must again mention what I published some two years since 



