AN ADEN US. 473 



" All the six specimens sent to me from Simla (where they were 

 collected during the rains in June and July, at the period when 

 they are in full activity and development), show the generative 

 orifice much expanded, with the male organ partly protruding. 

 This discloses the existence of several small, sharp, curved spines 

 fixed upon the surface of this reversed portion. On further 

 opening the generative orifice these curved spines were discovered 

 to be only the most advanced of a much greater number arranged in 

 two parallel rows and extending upwards, gradually lengthening, 

 and forming part of a very complicated and beautiful arrangement 

 of far longer and stronger calcareous spines. The frontal side of 

 this curious apparatus was found covered by a large and longi- 

 tudinally perforated plate, which had evidently been built up by 

 the union together at their upper and lower extremities of. 

 originally parallel spines. On the posterior side of this basal 

 portion of the male organ one very large, long, spear-shaped spine 

 was situated ; this measured 8 mm. in length. The whole of this 

 complicated structure must therefore be regarded as representing 

 the simple dart-sac with a single dart, as seen in other genera of 

 the HELICID^;, for the fixed position of the bases of these spines in 

 the integument of the lower swollen portion of the male organ 

 precludes the idea of its being a spermatophore. On following 

 the large duct of the penis upwards towards the junction with it 

 of the vas deferens, the end of the penis is seen, occupying the 

 upper swollen portion ; so that here we have apparently the penis 

 and the dart-sac almost united together, instead of, as is usual, the 

 dart contained in a distinct and long sac of its own ; but this, 

 after all, is only a question of degree, for the transition is seen in 

 such rudimentary pouches of the dart in Helix piscina (vide 

 pi. xix, fig. 16, Moquin-Tandon's ' Mollusques de France,' and 

 Helix bulimoides, pi. xx.). 



" Can it be that in this species the great development of spines 

 and this plate has converted this organ into one of a holding or 

 clipping nature on their interlocking or entanglement prior to, or 

 during the act of copulation ? for after expansion or protrusion 

 the muscular contraction would draw these spines together very 

 tightly. 



" One of the most interesting points in the anatomy of this 

 species is the relative position of the heart and renal organ, in 

 which respect it has a considerable similarity to what is seen in 

 Avion and Qeomalacut, encircling the heart. The position of the 

 ventricle is, however, different, on the posterior edge of the 

 mantle-cavity and directed backwards ; it is large and flatly pearl- 

 shaped. 



"The renal organ is ovate and is divided into two portions by 

 a main secretory duct, the inner portion forming a nearly complete 

 narrow disk round the ventricle and commencing from near where 

 the aorta is given off. The renal organ is quite free for three 

 quarters of its anterior margin, the dorsal surface being spread 

 over with the network of the pulmonary veins, the ventral surface 



