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.
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![[fVom the Annals and Magazine of Natural History for July 1861.] By harry SEELEY. IV. Some new Upper Greensand Echinoderms. Hemiaster M‘Coyii. Outline oblong, oval, slightly flattened at the anterior extremity, longer than wide; height two-thirds of the length. The most elevated part is a little behind the apex, the widest part a little anterior to the middle. The transverse section is oval. Upper side slightly convex, sloping down towards the anterior end. Under side slightly convex; the part anterior to the mouth depressed. Anal side nearly vertically truncated; anterior end round. Ambulacra straight, unequal, very slightly im- pressed. The odd ambulacrum is formed of straight zones, each composed of about a dozen pairs of round pores, which are placed obliquely and rather wide apart; the pores are close together. The anterior ambulacra consist of a similar number of pores, which are smaller and closer together. The posterior ambulacra are very short, the zones consisting of about four pairs of pores. Mouth transversely oval, bordered by a little groove, and placed in the anterior third of the shell. Anus oval. The fasciole is wide and 7-sided; it is angular posteriorly, with a short side anteriorly: the posterior and shorter pair of lateral sides is parallel; the granules of which it is formed are very dense, and only just visible to the naked eye. The shell is very thin, and covered with comparatively large tubercles. This well-marked Urchin is so distinct as not to admit of comparison with any form with which I am acquainted. Its - nearest relative is a more globular form which occurs with it. Rare. Coll. University ; J. Carter, Esq.](https://iiif.wellcomecollection.org/image/b22412426_0005.jp2/full/800%2C/0/default.jpg)
