OF THE MAKRAN SERIES. 378 



This is the form of Cidaris which approaches Goniocidaris, and was noticed in 

 the Description of the Fossil Echinoidea of Kachh and Kattywar, one of which appears 

 to be a true Goniocidaris (" Tert. Foss. Echin. Kachh and Kattywar," Pal. Ind. 

 Ser. XIV. 1883, p. 52). 



The broad median area, moderately crowded with very small tubercles and 

 granules, is very distinctive ; but there is much variation in regard to the amount of 

 sinking and doubtful pitting at the angles of the median suture. In a fragment of a 

 large individual there is barely any sinking whatever, and nothing to raise doubts 

 about the form being a Cidaris, except the broad interporiferous zone. On the other 

 hand a slightly smaller form, which approaches the type very closely, has great 

 affinities with Goniocidaris. 



The numerous spines which come from the same locality as tliese fragments are 

 all more like those of recent species of Goniocidaris than of Cidaris. 



2. CiDAKis, sp. Plate LVI, Fig. 3. 



There is a well-preserved fragment of a small Cidaris, which although having 

 affinities with the species just described, is to be distinguished by the absence of the 

 well-developed slope of the coronal plates, from the ring of small tubercles around the 

 scrobicular margin to the median line. In the species noticed above this surface is 

 covered with at least three rows of differently developed granules ; but in the present 

 instance the rows are wanting, and the tubercles around the elliptical scrobicular circle 

 have a row of large granules on a narrow surface between them and the well-indented 

 vertical sutures. Moreover, the line of secondary tubercles between the successive 

 vertical tubercles is sometimes absent and the scrobicules are continuous, or there is 

 but one, and not a very well-developed, row of secondaries in that position. 



The interporiferous part of an ambulacral plate is narrower than the poriferous 

 portion, and carries a small tubercle close to the adoral pore ; beyond is a smaller one, 

 and near the ambitus there may be one or two granules between the last-mentioned 

 tubercle and the median line. 



Locality. Henjam Island, Persian Gulf. Makran deposits. Survey-number 



n. 362 

 »J 5 • 



Illustration of the Specimen in Plate LVI. 

 Fig. 3. Coronal plates : magnified. 



Spines of CiDAEiDiE. Plate LVII. 



Spines of species of more than one genus of the family Cidaridae are common in 

 the white calcareous deposit, and they are not found in quite a perfect condition, for 

 the tops of the spiuules on them are broken off. Most of the spines are short, large, 

 and more or less compressed, and they may be grouped into three sets. 



1. Spines not very tall, cylindrical, irregularly and strongly spinulose, expanding 

 slightly at the summit, where there is a shallow hollow surrounded with spinules. 



