Notes on Cambridge palaeontology. IV. Some new Upper Greensand echinoderms / by Harry Seeley.
- Harry Govier Seeley
- Date:
- 1861
Licence: Public Domain Mark
Credit: Notes on Cambridge palaeontology. IV. Some new Upper Greensand echinoderms / by Harry Seeley. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
5/12 page 3
![with two rows of tubercles, which occupy the whole space, except towards the base, where a few others are introduced. From them descend short transverse ridges, forming pits, in which the pores are placed. The pairs of pores are in single file throughout. The interambulacra are furnished with two rows of tubercles of four each ; the uppermost of the left row is very large. The bosses are hemispherical and crenulated. The scrobiculse are surrounded by a row of granules. The peristome is rather pentagonal. Lat. inch, alt. inch ; oral opening inch j apical disk inch. This form is easily distinguished by the characters of the apical disk, the narrower ambulacral areas, larger interambulacral tubercles, small size, &c. It is one of the many unique treasures contained in the cabinet of my friend Mr. Carter, A single specimen has been found in which the following cha- racters may be generic :— Poles opposite. Apical opening moderate [cordate]. Oral open- ing entire, circular. Tubercles imperforate, crenulated. The ambulacral areas are half the width of the interambulacra. In them large tubercles are developed on one row of plates, and small tubercles on the other; in the interambulacral areas are two primary rows. Pores bigeminal. The pori- ferous zones are wide, and much impressed above. Should the characters presumed to be generic prove constant, the name Caseoltis might perhaps be used to indicate them. [? Ci/phosuma^ impressa. Pentagonal, greatly depressed, flattened above, concave below. Oral opening deeply sunk, circular. Apical aperture heart- shaped, extending into the odd interambulacrum. Ambulacra narrow, furnished with one row of about seven tubercles, which are as large as those of the interambulacra. On the other series of plates is a row of small granules, about three or four to each large plate: near the apex two or three small tubercles are developed. The poriferous zones are impressed on the upper part. The pores are placed in a straight line between elevated transverse ridges. There are two primary rows, and two secondary rows between these. In the inter- ambulacra ai’e two rows of tubercles of seven or eight each, Areolse large, radiated, scarcely impressed, nearly circular, and margined by a row of granules, which separates them A 2](https://iiif.wellcomecollection.org/image/b22412426_0007.jp2/full/800%2C/0/default.jpg)
