﻿140 SUPPLEMENT TO THE CRAG MOLLUSCA. 



various acknowledged species of this variable genus might be so selected as all to run 

 into one another and the whole of such species accordingly merged in one. In a genus 

 such as this, wherein the specific forms thus graduate into one another, and which, 

 moreover, goes back far into the Mezozoic formations with but little departure from the 

 living types, a more arbitrary line of specific division should be allowed than in the case 

 of species of less variable genera. 



Astarte Forbesii, S. Wood. Crag Moll, vol. ii, p. 192, Tab. XVII, fig. 12 a, b 



(as A. parva). 



Localities. Cor. Crag passim. 



When describing this shell I was not aware that the name of parva had been given 

 to another species in this genus ; but I find that a fossil, which is quite distinct, has 

 been so called by Dr. Lea (' Contrib. to Geol.,' p. 63, pi. 2, fig. 37), and as this is of 

 prior date (1833), my name, of course, must be suppressed. 



In a catalogue of the Mediterranean Mollusca by Mr. Jeffreys, published in the 

 £ Ann. and Mag. Nat. Hist.,' July, 1870, is the name Astarte parva, S. Wood; and that 

 gentleman there says, " This may possibly be A. pusitta of Forbes ; the inside margin is 

 notched in my specimens ;" and in the list by the same gentleman accompanying Mr. 

 Prestwich's Cor. Crag paper this identification is inserted without any qualification. 

 I have endeavoured to find out the type-specimens of Forbes' species, but unsuccessfully. 

 It is, however, described by Forbes as " concentrice striata, margine interno denticulato 

 but as the markings on my shell are eccentric instead of concentric, and the margin free 

 from denticulations, no greater discordance, so far as description goes, could well occur. 

 In general, where the full-grown shell of Astarte has a denticulated margin, the young 

 has this margin smooth, and as I have now before me one hundred specimens of this 

 Crag species, not one of which has a denticulated margin, I can hardly suppose them 

 all to be immature shells ; I therefore cannot with any propriety refer the Crag shell to 

 pusilla. It much resembles an Oligocene fossil named and described by Dr. Speyer as 

 Goodallia Koneni ('Die. Ober. Oligoc. Test. Detmold,' tab. iv, fig. 6, 1866), which is 

 ornamented with oblique ridges and has a smooth margin, but, judging from the represen- 

 tation, it is not a satisfactory identification ; therefore, until specimens can be compared, 

 and as the name parva must be abandoned, I have assigned to my shell the name 

 Forbesii. 



The late Mr. McAndrew gave me some specimens of a small Astarte which he 

 obtained in the living state off the Canaries, that much resembles the Cor. Crag shell 

 called A. parvula ; but I think the recent shell specifically different ; it is rather less 

 oblique, the lateral denticles of the recent shell are shorter, and the ventral margin is 

 denticulated. I have also a fossil specimen from Cannes, which is more shaped like 

 Mr. McAndrew's shell, but it has a smooth ventral margin. The following from the 

 Upper Tertiaries of East Anglia I consider as distinct species : 



