'880.] ON THE GENUS GIRASIA. 289 



1. Ou the LancI-MoUuscan Geiius Girasia of Gray, with 

 Remarks ou its Anatomy and on the Form of the 

 Capreolus of Lister (or Spermatophore) as developed 

 in Species of this Genus of Indian Helicid^. By 

 Lt.-Col. H. H. GoDWTN-AusTEN, F.Z.S., F.R.G.S., &c. 



[Received March 15, 1880.] 

 (Plates XXIV.-XXVII.). 



In certain groups of the Mohnsca the many forms run so 

 closely one into the other that it is not easy to find differences 

 sufficiently well marked by which to characterize even the genera. 

 The shells (which, as a rule, have alone been described) are often very 

 similar ; but in the animal itself, quite if not a more important part, 

 very great diversity may be found in colour and markings, as well 

 as in the complicated generative organs, amongst which the capreolus 

 presents us with another specific point of difference. 



This is one reason for my bringing it now more particularly to the 

 notice of conchologists, as well as to show iuto what curious distinct 

 forms it has been developed. I must state that I have not long 

 taken up this part of the study of Malacology ; and I trust that 

 anatomists will deal leniently with any crudeness which must be 

 inseparable from this communication. 



When examining a large series of Helices which I had collected 

 on the Eastern Frontier of India, I found that the body of many 

 of them had dried up into the shell in a very perfect state. By placing 

 these in cold water and allowing them to soak for 8 or 10 days 

 in vyinter, I found that the odontophore, and in some cases even the 

 genital organs, came out in a wonderfully perfect state of preserva- 

 tion. It was when examining one of these that I noticed the pre- 

 sence of a very hard chitinous organ (which I had never seen 

 before) bent like a spring, from which projected at the basal end a 

 series of lo;ig spinules : it tapered towards the posterior end, and 

 terminated in a trumpet-shaped aperture, here also set with a 

 few short spinules. Taking up the subject, I found that Ferd. 

 Stoliczka had also detected and published the presence of this very 

 peculiar chitinous organ in some species of the Indian Zonitidce, 

 and in two very different genera as regards the shells, viz. Sesara 

 infrendens &nA Macrochlamys honesta (J. A. S. B. 1871, p. 242) ; 

 and had he been spared longer to science, it was his intention to 

 thoroughly examine all the Indian species he could get, and among 

 them some of the slug-like forms hitherto placed in the genus 

 Helicarion, which I am about to describe in more detail. Stoliczka 

 suggested that the organ was one of irritation or titillation (p. 243, 

 /. c), also that it might represent the seminal receptacle or the arrow- 

 sac ; but Professor Semper afterwards pointed out (with reference to 

 Stoliczka's paper) that it is a spermatophore. 



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